Switch to vitest for ESM support; other fixes

22 files changed, 439 insertions, 1076 deletions

diff --git a/dev/bin/build-libs.js b/dev/bin/build-libs.js
new file mode 100644
index 00000000..07d27188
--- /dev/null
+++ b/dev/bin/build-libs.js
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2023  Yomitan Authors
+ * Copyright (C) 2020-2022  Yomichan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import {buildLibs} from '../build-libs.js';
+
+buildLibs();
diff --git a/dev/build.js b/dev/bin/build.js
index 1e6ef1d0..282f0414 100644
--- a/dev/build.js
+++ b/dev/bin/build.js
@@ -16,17 +16,17 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-const fs = require('fs');
-const path = require('path');
-const assert = require('assert');
-const readline = require('readline');
-const childProcess = require('child_process');
-const util = require('./util');
-const {getAllFiles, getArgs, testMain} = util;
-const {ManifestUtil} = require('./manifest-util');
-const Ajv = require('ajv');
-const standaloneCode = require('ajv/dist/standalone').default;
-const buildLibs = require('./build-libs.js').buildLibs;
+import assert from 'assert';
+import childProcess from 'child_process';
+import fs from 'fs';
+import path from 'path';
+import readline from 'readline';
+import {fileURLToPath} from 'url';
+import {buildLibs} from '../build-libs.js';
+import {ManifestUtil} from '../manifest-util.js';
+import {getAllFiles, getArgs, testMain} from '../util.js';
+
+const dirname = path.dirname(fileURLToPath(import.meta.url));
 
 async function createZip(directory, excludeFiles, outputFileName, sevenZipExes, onUpdate, dryRun) {
     try {
@@ -61,7 +61,7 @@ async function createZip(directory, excludeFiles, outputFileName, sevenZipExes,
 }
 
 async function createJSZip(directory, excludeFiles, outputFileName, onUpdate, dryRun) {
-    const JSZip = util.JSZip;
+    const JSZip = null;
     const files = getAllFiles(directory);
     removeItemsFromArray(files, excludeFiles);
     const zip = new JSZip();
@@ -132,19 +132,6 @@ async function build(buildDir, extDir, manifestUtil, variantNames, manifestPath,
         process.stdout.write(message);
     };
 
-    process.stdout.write('Building schema validators using ajv\n');
-    const schemaDir = path.join(extDir, 'data/schemas/');
-    const schemaFileNames = fs.readdirSync(schemaDir);
-    const schemas = schemaFileNames.map((schemaFileName) => JSON.parse(fs.readFileSync(path.join(schemaDir, schemaFileName))));
-    const ajv = new Ajv({schemas: schemas, code: {source: true, esm: true}});
-    const moduleCode = standaloneCode(ajv);
-
-    // https://github.com/ajv-validator/ajv/issues/2209
-    const patchedModuleCode = moduleCode.replaceAll('require("ajv/dist/runtime/ucs2length").default', 'import("/lib/ucs2length.js").default');
-
-    fs.writeFileSync(path.join(extDir, 'lib/validate-schemas.js'), patchedModuleCode);
-
-
     process.stdout.write(`Version: ${yomitanVersion}...\n`);
 
     for (const variantName of variantNames) {
@@ -193,7 +180,7 @@ function ensureFilesExist(directory, files) {
 }
 
 
-async function main(argv) {
+export async function main(argv) {
     const args = getArgs(argv, new Map([
         ['all', false],
         ['default', false],
@@ -210,7 +197,7 @@ async function main(argv) {
 
     const manifestUtil = new ManifestUtil();
 
-    const rootDir = path.join(__dirname, '..');
+    const rootDir = path.join(dirname, '..', '..');
     const extDir = path.join(rootDir, 'ext');
     const buildDir = path.join(rootDir, 'builds');
     const manifestPath = path.join(extDir, 'manifest.json');
@@ -234,12 +221,4 @@ async function main(argv) {
     }
 }
 
-
-if (require.main === module) {
-    testMain(main, process.argv.slice(2));
-}
-
-
-module.exports = {
-    main
-};
+testMain(main, process.argv.slice(2));
diff --git a/dev/bin/dictionary-validate.js b/dev/bin/dictionary-validate.js
new file mode 100644
index 00000000..78ad5198
--- /dev/null
+++ b/dev/bin/dictionary-validate.js
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2023  Yomitan Authors
+ * Copyright (C) 2020-2022  Yomichan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import {testDictionaryFiles} from '../dictionary-validate.js';
+
+async function main() {
+    const dictionaryFileNames = process.argv.slice(2);
+    if (dictionaryFileNames.length === 0) {
+        console.log([
+            'Usage:',
+            '  node dictionary-validate [--ajv] <dictionary-file-names>...'
+        ].join('\n'));
+        return;
+    }
+
+    let mode = null;
+    if (dictionaryFileNames[0] === '--ajv') {
+        mode = 'ajv';
+        dictionaryFileNames.splice(0, 1);
+    }
+
+    await testDictionaryFiles(mode, dictionaryFileNames);
+}
+
+main();
diff --git a/dev/bin/generate-css-json.js b/dev/bin/generate-css-json.js
new file mode 100644
index 00000000..48b42c65
--- /dev/null
+++ b/dev/bin/generate-css-json.js
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2023  Yomitan Authors
+ * Copyright (C) 2020-2022  Yomichan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import fs from 'fs';
+import {formatRulesJson, generateRules, getTargets} from '../generate-css-json.js';
+
+function main() {
+    for (const {cssFile, overridesCssFile, outputPath} of getTargets()) {
+        const json = formatRulesJson(generateRules(cssFile, overridesCssFile));
+        fs.writeFileSync(outputPath, json, {encoding: 'utf8'});
+    }
+}
+
+main();
diff --git a/dev/bin/schema-validate.js b/dev/bin/schema-validate.js
new file mode 100644
index 00000000..86cfebae
--- /dev/null
+++ b/dev/bin/schema-validate.js
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2023  Yomitan Authors
+ * Copyright (C) 2020-2022  Yomichan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import fs from 'fs';
+import performance from 'perf_hooks';
+import {createJsonSchema} from '../util.js';
+
+function main() {
+    const args = process.argv.slice(2);
+    if (args.length < 2) {
+        console.log([
+            'Usage:',
+            '  node schema-validate [--ajv] <schema-file-name> <data-file-names>...'
+        ].join('\n'));
+        return;
+    }
+
+    let mode = null;
+    if (args[0] === '--ajv') {
+        mode = 'ajv';
+        args.splice(0, 1);
+    }
+
+    const schemaSource = fs.readFileSync(args[0], {encoding: 'utf8'});
+    const schema = JSON.parse(schemaSource);
+
+    for (const dataFileName of args.slice(1)) {
+        const start = performance.now();
+        try {
+            console.log(`Validating ${dataFileName}...`);
+            const dataSource = fs.readFileSync(dataFileName, {encoding: 'utf8'});
+            const data = JSON.parse(dataSource);
+            createJsonSchema(mode, schema).validate(data);
+            const end = performance.now();
+            console.log(`No issues detected (${((end - start) / 1000).toFixed(2)}s)`);
+        } catch (e) {
+            const end = performance.now();
+            console.log(`Encountered an error (${((end - start) / 1000).toFixed(2)}s)`);
+            console.warn(e);
+        }
+    }
+}
+
+
+main();
diff --git a/dev/build-libs.js b/dev/build-libs.js
index 497206c9..8320a947 100644
--- a/dev/build-libs.js
+++ b/dev/build-libs.js
@@ -16,9 +16,15 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-const fs = require('fs');
-const path = require('path');
-const esbuild = require('esbuild');
+import Ajv from 'ajv';
+import standaloneCode from 'ajv/dist/standalone/index.js';
+import esbuild from 'esbuild';
+import fs from 'fs';
+import path from 'path';
+import {fileURLToPath} from 'url';
+
+const dirname = path.dirname(fileURLToPath(import.meta.url));
+const extDir = path.join(dirname, '..', 'ext');
 
 async function buildLib(p) {
     await esbuild.build({
@@ -28,13 +34,13 @@ async function buildLib(p) {
         sourcemap: true,
         target: 'es2020',
         format: 'esm',
-        outfile: path.join(__dirname, '..', 'ext', 'lib', path.basename(p)),
+        outfile: path.join(extDir, 'lib', path.basename(p)),
         external: ['fs']
     });
 }
 
-async function buildLibs() {
-    const devLibPath = path.join(__dirname, 'lib');
+export async function buildLibs() {
+    const devLibPath = path.join(dirname, 'lib');
     const files = await fs.promises.readdir(devLibPath, {
         withFileTypes: true
     });
@@ -43,10 +49,15 @@ async function buildLibs() {
             await buildLib(path.join(devLibPath, f.name));
         }
     }
-}
 
-if (require.main === module) { buildLibs(); }
+    const schemaDir = path.join(extDir, 'data/schemas/');
+    const schemaFileNames = fs.readdirSync(schemaDir);
+    const schemas = schemaFileNames.map((schemaFileName) => JSON.parse(fs.readFileSync(path.join(schemaDir, schemaFileName))));
+    const ajv = new Ajv({schemas: schemas, code: {source: true, esm: true}});
+    const moduleCode = standaloneCode(ajv);
 
-module.exports = {
-    buildLibs
-};
+    // https://github.com/ajv-validator/ajv/issues/2209
+    const patchedModuleCode = "import {ucs2length} from './ucs2length.js';" + moduleCode.replaceAll('require("ajv/dist/runtime/ucs2length").default', 'ucs2length');
+
+    fs.writeFileSync(path.join(extDir, 'lib/validate-schemas.js'), patchedModuleCode);
+}
diff --git a/dev/css-to-json-util.js b/dev/css-to-json-util.js
deleted file mode 100644
index 79aae3c9..00000000
--- a/dev/css-to-json-util.js
+++ /dev/null
@@ -1,172 +0,0 @@
-/*
- * Copyright (C) 2023  Yomitan Authors
- * Copyright (C) 2021-2022  Yomichan Authors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-const fs = require('fs');
-const css = require('css');
-
-function indexOfRule(rules, selectors) {
-    const jj = selectors.length;
-    for (let i = 0, ii = rules.length; i < ii; ++i) {
-        const ruleSelectors = rules[i].selectors;
-        if (ruleSelectors.length !== jj) { continue; }
-        let okay = true;
-        for (let j = 0; j < jj; ++j) {
-            if (selectors[j] !== ruleSelectors[j]) {
-                okay = false;
-                break;
-            }
-        }
-        if (okay) { return i; }
-    }
-    return -1;
-}
-
-function removeProperty(styles, property, removedProperties) {
-    let removeCount = removedProperties.get(property);
-    if (typeof removeCount !== 'undefined') { return removeCount; }
-    removeCount = 0;
-    for (let i = 0, ii = styles.length; i < ii; ++i) {
-        const key = styles[i][0];
-        if (key !== property) { continue; }
-        styles.splice(i, 1);
-        --i;
-        --ii;
-        ++removeCount;
-    }
-    removedProperties.set(property, removeCount);
-    return removeCount;
-}
-
-function formatRulesJson(rules) {
-    // Manually format JSON, for improved compactness
-    // return JSON.stringify(rules, null, 4);
-    const indent1 = '    ';
-    const indent2 = indent1.repeat(2);
-    const indent3 = indent1.repeat(3);
-    let result = '';
-    result += '[';
-    let index1 = 0;
-    for (const {selectors, styles} of rules) {
-        if (index1 > 0) { result += ','; }
-        result += `\n${indent1}{\n${indent2}"selectors": `;
-        if (selectors.length === 1) {
-            result += `[${JSON.stringify(selectors[0], null, 4)}]`;
-        } else {
-            result += JSON.stringify(selectors, null, 4).replace(/\n/g, '\n' + indent2);
-        }
-        result += `,\n${indent2}"styles": [`;
-        let index2 = 0;
-        for (const [key, value] of styles) {
-            if (index2 > 0) { result += ','; }
-            result += `\n${indent3}[${JSON.stringify(key)}, ${JSON.stringify(value)}]`;
-            ++index2;
-        }
-        if (index2 > 0) { result += `\n${indent2}`; }
-        result += `]\n${indent1}}`;
-        ++index1;
-    }
-    if (index1 > 0) { result += '\n'; }
-    result += ']';
-    return result;
-}
-
-function generateRules(cssFile, overridesCssFile) {
-    const content1 = fs.readFileSync(cssFile, {encoding: 'utf8'});
-    const content2 = fs.readFileSync(overridesCssFile, {encoding: 'utf8'});
-    const stylesheet1 = css.parse(content1, {}).stylesheet;
-    const stylesheet2 = css.parse(content2, {}).stylesheet;
-
-    const removePropertyPattern = /^remove-property\s+([\w\W]+)$/;
-    const removeRulePattern = /^remove-rule$/;
-    const propertySeparator = /\s+/;
-
-    const rules = [];
-
-    // Default stylesheet
-    for (const rule of stylesheet1.rules) {
-        if (rule.type !== 'rule') { continue; }
-        const {selectors, declarations} = rule;
-        const styles = [];
-        for (const declaration of declarations) {
-            if (declaration.type !== 'declaration') { console.log(declaration); continue; }
-            const {property, value} = declaration;
-            styles.push([property, value]);
-        }
-        if (styles.length > 0) {
-            rules.push({selectors, styles});
-        }
-    }
-
-    // Overrides
-    for (const rule of stylesheet2.rules) {
-        if (rule.type !== 'rule') { continue; }
-        const {selectors, declarations} = rule;
-        const removedProperties = new Map();
-        for (const declaration of declarations) {
-            switch (declaration.type) {
-                case 'declaration':
-                    {
-                        const index = indexOfRule(rules, selectors);
-                        let entry;
-                        if (index >= 0) {
-                            entry = rules[index];
-                        } else {
-                            entry = {selectors, styles: []};
-                            rules.push(entry);
-                        }
-                        const {property, value} = declaration;
-                        removeProperty(entry.styles, property, removedProperties);
-                        entry.styles.push([property, value]);
-                    }
-                    break;
-                case 'comment':
-                    {
-                        const index = indexOfRule(rules, selectors);
-                        if (index < 0) { throw new Error('Could not find rule with matching selectors'); }
-                        const comment = declaration.comment.trim();
-                        let m;
-                        if ((m = removePropertyPattern.exec(comment)) !== null) {
-                            for (const property of m[1].split(propertySeparator)) {
-                                const removeCount = removeProperty(rules[index].styles, property, removedProperties);
-                                if (removeCount === 0) { throw new Error(`Property removal is unnecessary; ${property} does not exist`); }
-                            }
-                        } else if (removeRulePattern.test(comment)) {
-                            rules.splice(index, 1);
-                        }
-                    }
-                    break;
-            }
-        }
-    }
-
-    // Remove empty
-    for (let i = 0, ii = rules.length; i < ii; ++i) {
-        if (rules[i].styles.length > 0) { continue; }
-        rules.splice(i, 1);
-        --i;
-        --ii;
-    }
-
-    return rules;
-}
-
-
-module.exports = {
-    formatRulesJson,
-    generateRules
-};
diff --git a/dev/data/manifest-variants.json b/dev/data/manifest-variants.json
index d44251e1..e6113b75 100644
--- a/dev/data/manifest-variants.json
+++ b/dev/data/manifest-variants.json
@@ -122,8 +122,7 @@
             "inherit": "base",
             "fileName": "yomitan-chrome.zip",
             "excludeFiles": [
-                "background.html",
-                "js/dom/native-simple-dom-parser.js"
+                "background.html"
             ]
         },
         {
@@ -187,6 +186,13 @@
                     ]
                 },
                 {
+                    "action": "delete",
+                    "path": [
+                        "background",
+                        "type"
+                    ]
+                },
+                {
                     "action": "set",
                     "path": [
                         "background",
@@ -251,9 +257,7 @@
                 "sw.js",
                 "offscreen.html",
                 "js/background/offscreen.js",
-                "js/background/offscreen-main.js",
-                "js/dom/simple-dom-parser.js",
-                "lib/parse5.js"
+                "js/background/offscreen-main.js"
             ]
         },
         {
@@ -302,9 +306,7 @@
                 "sw.js",
                 "offscreen.html",
                 "js/background/offscreen.js",
-                "js/background/offscreen-main.js",
-                "js/dom/simple-dom-parser.js",
-                "lib/parse5.js"
+                "js/background/offscreen-main.js"
             ]
         },
         {
@@ -351,9 +353,7 @@
                 "sw.js",
                 "offscreen.html",
                 "js/background/offscreen.js",
-                "js/background/offscreen-main.js",
-                "js/dom/simple-dom-parser.js",
-                "lib/parse5.js"
+                "js/background/offscreen-main.js"
             ]
         }
     ]
diff --git a/dev/database-vm.js b/dev/database-vm.js
deleted file mode 100644
index d5570691..00000000
--- a/dev/database-vm.js
+++ /dev/null
@@ -1,82 +0,0 @@
-/*
- * Copyright (C) 2023  Yomitan Authors
- * Copyright (C) 2020-2022  Yomichan Authors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-const fs = require('fs');
-const url = require('url');
-const path = require('path');
-const {JSZip} = require('./util');
-const {VM} = require('./vm');
-require('fake-indexeddb/auto');
-
-const chrome = {
-    runtime: {
-        getURL: (path2) => {
-            return url.pathToFileURL(path.join(__dirname, '..', 'ext', path2.replace(/^\//, ''))).href;
-        }
-    }
-};
-
-async function fetch(url2) {
-    const extDir = path.join(__dirname, '..', 'ext');
-    let filePath;
-    try {
-        filePath = url.fileURLToPath(url2);
-    } catch (e) {
-        filePath = path.resolve(extDir, url2.replace(/^[/\\]/, ''));
-    }
-    await Promise.resolve();
-    const content = fs.readFileSync(filePath, {encoding: null});
-    return {
-        ok: true,
-        status: 200,
-        statusText: 'OK',
-        text: async () => Promise.resolve(content.toString('utf8')),
-        json: async () => Promise.resolve(JSON.parse(content.toString('utf8')))
-    };
-}
-
-function atob(data) {
-    return Buffer.from(data, 'base64').toString('ascii');
-}
-
-class DatabaseVM extends VM {
-    constructor(globals={}) {
-        super(Object.assign({
-            chrome,
-            fetch,
-            indexedDB: global.indexedDB,
-            IDBKeyRange: global.IDBKeyRange,
-            JSZip,
-            atob
-        }, globals));
-        this.context.window = this.context;
-        this.indexedDB = global.indexedDB;
-    }
-}
-
-class DatabaseVMDictionaryImporterMediaLoader {
-    async getImageDetails(content) {
-        // Placeholder values
-        return {content, width: 100, height: 100};
-    }
-}
-
-module.exports = {
-    DatabaseVM,
-    DatabaseVMDictionaryImporterMediaLoader
-};
diff --git a/dev/dictionary-validate.js b/dev/dictionary-validate.js
index 0c926acc..eb40beda 100644
--- a/dev/dictionary-validate.js
+++ b/dev/dictionary-validate.js
@@ -16,12 +16,11 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-const fs = require('fs');
-const path = require('path');
-const {performance} = require('perf_hooks');
-const {JSZip} = require('./util');
-const {createJsonSchema} = require('./schema-validate');
-
+import fs from 'fs';
+import JSZip from 'jszip';
+import path from 'path';
+import {performance} from 'perf_hooks';
+import {createJsonSchema} from './schema-validate.js';
 
 function readSchema(relativeFileName) {
     const fileName = path.join(__dirname, relativeFileName);
@@ -29,7 +28,6 @@ function readSchema(relativeFileName) {
     return JSON.parse(source);
 }
 
-
 async function validateDictionaryBanks(mode, zip, fileNameFormat, schema) {
     let jsonSchema;
     try {
@@ -57,7 +55,7 @@ async function validateDictionaryBanks(mode, zip, fileNameFormat, schema) {
     }
 }
 
-async function validateDictionary(mode, archive, schemas) {
+export async function validateDictionary(mode, archive, schemas) {
     const fileName = 'index.json';
     const indexFile = archive.files[fileName];
     if (!indexFile) {
@@ -82,7 +80,7 @@ async function validateDictionary(mode, archive, schemas) {
     await validateDictionaryBanks(mode, archive, 'tag_bank_?.json', schemas.tagBankV3);
 }
 
-function getSchemas() {
+export function getSchemas() {
     return {
         index: readSchema('../ext/data/schemas/dictionary-index-schema.json'),
         kanjiBankV1: readSchema('../ext/data/schemas/dictionary-kanji-bank-v1-schema.json'),
@@ -95,8 +93,7 @@ function getSchemas() {
     };
 }
 
-
-async function testDictionaryFiles(mode, dictionaryFileNames) {
+export async function testDictionaryFiles(mode, dictionaryFileNames) {
     const schemas = getSchemas();
 
     for (const dictionaryFileName of dictionaryFileNames) {
@@ -115,33 +112,3 @@ async function testDictionaryFiles(mode, dictionaryFileNames) {
         }
     }
 }
-
-
-async function main() {
-    const dictionaryFileNames = process.argv.slice(2);
-    if (dictionaryFileNames.length === 0) {
-        console.log([
-            'Usage:',
-            '  node dictionary-validate [--ajv] <dictionary-file-names>...'
-        ].join('\n'));
-        return;
-    }
-
-    let mode = null;
-    if (dictionaryFileNames[0] === '--ajv') {
-        mode = 'ajv';
-        dictionaryFileNames.splice(0, 1);
-    }
-
-    await testDictionaryFiles(mode, dictionaryFileNames);
-}
-
-
-if (require.main === module) { main(); }
-
-
-module.exports = {
-    getSchemas,
-    validateDictionary,
-    testDictionaryFiles
-};
diff --git a/dev/generate-css-json.js b/dev/generate-css-json.js
index 787173ab..914c1452 100644
--- a/dev/generate-css-json.js
+++ b/dev/generate-css-json.js
@@ -16,12 +16,10 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-const fs = require('fs');
-const path = require('path');
-const {testMain} = require('./util');
-const {formatRulesJson, generateRules} = require('./css-to-json-util');
+import fs from 'fs';
+import path from 'path';
 
-function getTargets() {
+export function getTargets() {
     return [
         {
             cssFile: path.join(__dirname, '..', 'ext/css/structured-content.css'),
@@ -36,19 +34,150 @@ function getTargets() {
     ];
 }
 
-function main() {
-    for (const {cssFile, overridesCssFile, outputPath} of getTargets()) {
-        const json = formatRulesJson(generateRules(cssFile, overridesCssFile));
-        fs.writeFileSync(outputPath, json, {encoding: 'utf8'});
+import css from 'css';
+
+function indexOfRule(rules, selectors) {
+    const jj = selectors.length;
+    for (let i = 0, ii = rules.length; i < ii; ++i) {
+        const ruleSelectors = rules[i].selectors;
+        if (ruleSelectors.length !== jj) { continue; }
+        let okay = true;
+        for (let j = 0; j < jj; ++j) {
+            if (selectors[j] !== ruleSelectors[j]) {
+                okay = false;
+                break;
+            }
+        }
+        if (okay) { return i; }
     }
+    return -1;
 }
 
+function removeProperty(styles, property, removedProperties) {
+    let removeCount = removedProperties.get(property);
+    if (typeof removeCount !== 'undefined') { return removeCount; }
+    removeCount = 0;
+    for (let i = 0, ii = styles.length; i < ii; ++i) {
+        const key = styles[i][0];
+        if (key !== property) { continue; }
+        styles.splice(i, 1);
+        --i;
+        --ii;
+        ++removeCount;
+    }
+    removedProperties.set(property, removeCount);
+    return removeCount;
+}
 
-if (require.main === module) {
-    testMain(main, process.argv.slice(2));
+export function formatRulesJson(rules) {
+    // Manually format JSON, for improved compactness
+    // return JSON.stringify(rules, null, 4);
+    const indent1 = '    ';
+    const indent2 = indent1.repeat(2);
+    const indent3 = indent1.repeat(3);
+    let result = '';
+    result += '[';
+    let index1 = 0;
+    for (const {selectors, styles} of rules) {
+        if (index1 > 0) { result += ','; }
+        result += `\n${indent1}{\n${indent2}"selectors": `;
+        if (selectors.length === 1) {
+            result += `[${JSON.stringify(selectors[0], null, 4)}]`;
+        } else {
+            result += JSON.stringify(selectors, null, 4).replace(/\n/g, '\n' + indent2);
+        }
+        result += `,\n${indent2}"styles": [`;
+        let index2 = 0;
+        for (const [key, value] of styles) {
+            if (index2 > 0) { result += ','; }
+            result += `\n${indent3}[${JSON.stringify(key)}, ${JSON.stringify(value)}]`;
+            ++index2;
+        }
+        if (index2 > 0) { result += `\n${indent2}`; }
+        result += `]\n${indent1}}`;
+        ++index1;
+    }
+    if (index1 > 0) { result += '\n'; }
+    result += ']';
+    return result;
 }
 
+export function generateRules(cssFile, overridesCssFile) {
+    const content1 = fs.readFileSync(cssFile, {encoding: 'utf8'});
+    const content2 = fs.readFileSync(overridesCssFile, {encoding: 'utf8'});
+    const stylesheet1 = css.parse(content1, {}).stylesheet;
+    const stylesheet2 = css.parse(content2, {}).stylesheet;
+
+    const removePropertyPattern = /^remove-property\s+([\w\W]+)$/;
+    const removeRulePattern = /^remove-rule$/;
+    const propertySeparator = /\s+/;
 
-module.exports = {
-    getTargets
-};
+    const rules = [];
+
+    // Default stylesheet
+    for (const rule of stylesheet1.rules) {
+        if (rule.type !== 'rule') { continue; }
+        const {selectors, declarations} = rule;
+        const styles = [];
+        for (const declaration of declarations) {
+            if (declaration.type !== 'declaration') { console.log(declaration); continue; }
+            const {property, value} = declaration;
+            styles.push([property, value]);
+        }
+        if (styles.length > 0) {
+            rules.push({selectors, styles});
+        }
+    }
+
+    // Overrides
+    for (const rule of stylesheet2.rules) {
+        if (rule.type !== 'rule') { continue; }
+        const {selectors, declarations} = rule;
+        const removedProperties = new Map();
+        for (const declaration of declarations) {
+            switch (declaration.type) {
+                case 'declaration':
+                    {
+                        const index = indexOfRule(rules, selectors);
+                        let entry;
+                        if (index >= 0) {
+                            entry = rules[index];
+                        } else {
+                            entry = {selectors, styles: []};
+                            rules.push(entry);
+                        }
+                        const {property, value} = declaration;
+                        removeProperty(entry.styles, property, removedProperties);
+                        entry.styles.push([property, value]);
+                    }
+                    break;
+                case 'comment':
+                    {
+                        const index = indexOfRule(rules, selectors);
+                        if (index < 0) { throw new Error('Could not find rule with matching selectors'); }
+                        const comment = declaration.comment.trim();
+                        let m;
+                        if ((m = removePropertyPattern.exec(comment)) !== null) {
+                            for (const property of m[1].split(propertySeparator)) {
+                                const removeCount = removeProperty(rules[index].styles, property, removedProperties);
+                                if (removeCount === 0) { throw new Error(`Property removal is unnecessary; ${property} does not exist`); }
+                            }
+                        } else if (removeRulePattern.test(comment)) {
+                            rules.splice(index, 1);
+                        }
+                    }
+                    break;
+            }
+        }
+    }
+
+    // Remove empty
+    for (let i = 0, ii = rules.length; i < ii; ++i) {
+        if (rules[i].styles.length > 0) { continue; }
+        rules.splice(i, 1);
+        --i;
+        --ii;
+    }
+
+    return rules;
+}
diff --git a/dev/lib/ucs2length.js b/dev/lib/ucs2length.js
index 2e4a01cd..3b370493 100644
--- a/dev/lib/ucs2length.js
+++ b/dev/lib/ucs2length.js
@@ -14,5 +14,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
-export {ucs2length} from 'ajv/dist/runtime/ucs2length';
+import ucs2length from 'ajv/dist/runtime/ucs2length.js';
+const ucs2length2 = ucs2length.default;
+export {ucs2length2 as ucs2length};
 
diff --git a/dev/lib/z-worker.js b/dev/lib/z-worker.js
new file mode 100644
index 00000000..f6a95ed3
--- /dev/null
+++ b/dev/lib/z-worker.js
@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2023  Yomitan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+import '../../node_modules/@zip.js/zip.js/lib/z-worker.js';
diff --git a/dev/lib/zip.js b/dev/lib/zip.js
index 7560f5f8..b6e85451 100644
--- a/dev/lib/zip.js
+++ b/dev/lib/zip.js
@@ -14,4 +14,4 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
-export * from '@zip.js/zip.js/lib/zip-full.js';
+export * from '@zip.js/zip.js/lib/zip.js';
diff --git a/dev/lint/global-declarations.js b/dev/lint/global-declarations.js
deleted file mode 100644
index 7f90d227..00000000
--- a/dev/lint/global-declarations.js
+++ /dev/null
@@ -1,133 +0,0 @@
-/*
- * Copyright (C) 2023  Yomitan Authors
- * Copyright (C) 2020-2022  Yomichan Authors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-const fs = require('fs');
-const path = require('path');
-const assert = require('assert');
-const {getAllFiles} = require('../util');
-
-
-function escapeRegExp(string) {
-    return string.replace(/[.*+\-?^${}()|[\]\\]/g, '\\$&');
-}
-
-function countOccurences(string, pattern) {
-    return (string.match(pattern) || []).length;
-}
-
-function getNewline(string) {
-    const count1 = countOccurences(string, /(?:^|[^\r])\n/g);
-    const count2 = countOccurences(string, /\r\n/g);
-    const count3 = countOccurences(string, /\r(?:[^\n]|$)/g);
-    if (count2 > count1) {
-        return (count3 > count2) ? '\r' : '\r\n';
-    } else {
-        return (count3 > count1) ? '\r' : '\n';
-    }
-}
-
-function getSubstringCount(string, substring) {
-    let count = 0;
-    const pattern = new RegExp(`\\b${escapeRegExp(substring)}\\b`, 'g');
-    while (true) {
-        const match = pattern.exec(string);
-        if (match === null) { break; }
-        ++count;
-    }
-    return count;
-}
-
-
-function validateGlobals(fileName, fix) {
-    const pattern = /\/\*\s*global\s+([\w\W]*?)\*\//g;
-    const trimPattern = /^[\s,*]+|[\s,*]+$/g;
-    const splitPattern = /[\s,*]+/;
-    const source = fs.readFileSync(fileName, {encoding: 'utf8'});
-    let match;
-    let first = true;
-    let endIndex = 0;
-    let newSource = '';
-    const allGlobals = [];
-    const newline = getNewline(source);
-    while ((match = pattern.exec(source)) !== null) {
-        if (!first) {
-            console.error(`Encountered more than one global declaration in ${fileName}`);
-            return false;
-        }
-        first = false;
-
-        const parts = match[1].replace(trimPattern, '').split(splitPattern);
-        parts.sort();
-
-        const actual = match[0];
-        const expected = `/* global${parts.map((v) => `${newline} * ${v}`).join('')}${newline} */`;
-
-        try {
-            assert.strictEqual(actual, expected);
-        } catch (e) {
-            console.error(`Global declaration error encountered in ${fileName}:`);
-            console.error(e.message);
-            if (!fix) {
-                return false;
-            }
-        }
-
-        newSource += source.substring(0, match.index);
-        newSource += expected;
-        endIndex = match.index + match[0].length;
-
-        allGlobals.push(...parts);
-    }
-
-    newSource += source.substring(endIndex);
-
-    // This is an approximate check to see if a global variable is unused.
-    // If the global appears in a comment, string, or similar, the check will pass.
-    let errorCount = 0;
-    for (const global of allGlobals) {
-        if (getSubstringCount(newSource, global) <= 1) {
-            console.error(`Global variable ${global} appears to be unused in ${fileName}`);
-            ++errorCount;
-        }
-    }
-
-    if (fix) {
-        fs.writeFileSync(fileName, newSource, {encoding: 'utf8'});
-    }
-
-    return errorCount === 0;
-}
-
-
-function main() {
-    const fix = (process.argv.length >= 2 && process.argv[2] === '--fix');
-    const directory = path.resolve(__dirname, '..', '..', 'ext');
-    const pattern = /\.js$/;
-    const ignorePattern = /^lib[\\/]/;
-    const fileNames = getAllFiles(directory, (f) => pattern.test(f) && !ignorePattern.test(f));
-    for (const fileName of fileNames) {
-        if (!validateGlobals(path.join(directory, fileName), fix)) {
-            process.exit(-1);
-            return;
-        }
-    }
-    process.exit(0);
-}
-
-
-if (require.main === module) { main(); }
diff --git a/dev/lint/html-scripts.js b/dev/lint/html-scripts.js
deleted file mode 100644
index db6e6ca4..00000000
--- a/dev/lint/html-scripts.js
+++ /dev/null
@@ -1,173 +0,0 @@
-/*
- * Copyright (C) 2023  Yomitan Authors
- * Copyright (C) 2020-2022  Yomichan Authors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-const fs = require('fs');
-const path = require('path');
-const assert = require('assert');
-const {JSDOM} = require('jsdom');
-const {getAllFiles} = require('../util');
-
-
-function lstatSyncSafe(fileName) {
-    try {
-        return fs.lstatSync(fileName);
-    } catch (e) {
-        return null;
-    }
-}
-
-function validatePath(src, fileName, extDir) {
-    assert.ok(typeof src === 'string', `<script> missing src attribute in ${fileName}`);
-    assert.ok(src.startsWith('/'), `<script> src attribute is not absolute in ${fileName} (src=${JSON.stringify(src)})`);
-    const relativeSrc = src.substring(1);
-    assert.ok(!path.isAbsolute(relativeSrc), `<script> src attribute is invalid in ${fileName} (src=${JSON.stringify(src)})`);
-    const fullSrc = path.join(extDir, relativeSrc);
-    const stats = lstatSyncSafe(fullSrc);
-    assert.ok(stats !== null, `<script> src file not found in ${fileName} (src=${JSON.stringify(src)})`);
-    assert.ok(stats.isFile(), `<script> src file invalid in ${fileName} (src=${JSON.stringify(src)})`);
-}
-
-function getSubstringCount(string, pattern) {
-    let count = 0;
-    while (true) {
-        const match = pattern.exec(string);
-        if (match === null) { break; }
-        ++count;
-    }
-    return count;
-}
-
-function getSortedScriptPaths(scriptPaths) {
-    // Sort file names without the extension
-    const extensionPattern = /\.[^.]*$/;
-    scriptPaths = scriptPaths.map((value) => {
-        const match = extensionPattern.exec(value);
-        let ext = '';
-        if (match !== null) {
-            ext = match[0];
-            value = value.substring(0, value.length - ext.length);
-        }
-        return {value, ext};
-    });
-
-    const stringComparer = new Intl.Collator('en-US'); // Invariant locale
-    scriptPaths.sort((a, b) => stringComparer.compare(a.value, b.value));
-
-    scriptPaths = scriptPaths.map(({value, ext}) => `${value}${ext}`);
-    return scriptPaths;
-}
-
-function validateScriptOrder(fileName, window) {
-    const {document, Node: {ELEMENT_NODE, TEXT_NODE}, NodeFilter} = window;
-
-    const scriptElements = document.querySelectorAll('script');
-    if (scriptElements.length === 0) { return; }
-
-    // Assert all scripts are siblings
-    const scriptContainerElement = scriptElements[0].parentNode;
-    for (const element of scriptElements) {
-        if (element.parentNode !== scriptContainerElement) {
-            assert.fail('All script nodes are not contained within the same element');
-        }
-    }
-
-    // Get script groupings and order
-    const scriptGroups = [];
-    const newlinePattern = /\n/g;
-    let separatingText = '';
-    const walker = document.createTreeWalker(scriptContainerElement, NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_TEXT);
-    walker.firstChild();
-    for (let node = walker.currentNode; node !== null; node = walker.nextSibling()) {
-        switch (node.nodeType) {
-            case ELEMENT_NODE:
-                if (node.tagName.toLowerCase() === 'script') {
-                    let scriptGroup;
-                    if (scriptGroups.length === 0 || getSubstringCount(separatingText, newlinePattern) >= 2) {
-                        scriptGroup = [];
-                        scriptGroups.push(scriptGroup);
-                    } else {
-                        scriptGroup = scriptGroups[scriptGroups.length - 1];
-                    }
-                    scriptGroup.push(node.src);
-                    separatingText = '';
-                }
-                break;
-            case TEXT_NODE:
-                separatingText += node.nodeValue;
-                break;
-        }
-    }
-
-    // Ensure core.js is first (if it is present)
-    const ignorePattern = /^\/lib\//;
-    const index = scriptGroups.flat()
-        .filter((value) => !ignorePattern.test(value))
-        .findIndex((value) => (value === '/js/core.js'));
-    assert.ok(index <= 0, 'core.js is not the first included script');
-
-    // Check script order
-    for (let i = 0, ii = scriptGroups.length; i < ii; ++i) {
-        const scriptGroup = scriptGroups[i];
-        try {
-            assert.deepStrictEqual(scriptGroup, getSortedScriptPaths(scriptGroup));
-        } catch (e) {
-            console.error(`Script order for group ${i + 1} in file ${fileName} is not correct:`);
-            throw e;
-        }
-    }
-}
-
-function validateHtmlScripts(fileName, extDir) {
-    const fullFileName = path.join(extDir, fileName);
-    const domSource = fs.readFileSync(fullFileName, {encoding: 'utf8'});
-    const dom = new JSDOM(domSource);
-    const {window} = dom;
-    const {document} = window;
-    try {
-        for (const {src} of document.querySelectorAll('script')) {
-            validatePath(src, fullFileName, extDir);
-        }
-        for (const {href} of document.querySelectorAll('link')) {
-            validatePath(href, fullFileName, extDir);
-        }
-        validateScriptOrder(fileName, window);
-    } finally {
-        window.close();
-    }
-}
-
-
-function main() {
-    try {
-        const extDir = path.resolve(__dirname, '..', '..', 'ext');
-        const pattern = /\.html$/;
-        const ignorePattern = /^lib[\\/]/;
-        const fileNames = getAllFiles(extDir, (f) => pattern.test(f) && !ignorePattern.test(f));
-        for (const fileName of fileNames) {
-            validateHtmlScripts(fileName, extDir);
-        }
-    } catch (e) {
-        console.error(e);
-        process.exit(-1);
-        return;
-    }
-    process.exit(0);
-}
-
-
-if (require.main === module) { main(); }
diff --git a/dev/manifest-util.js b/dev/manifest-util.js
index 082cf57c..15175e7f 100644
--- a/dev/manifest-util.js
+++ b/dev/manifest-util.js
@@ -16,19 +16,21 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-const fs = require('fs');
-const path = require('path');
-const childProcess = require('child_process');
+import childProcess from 'child_process';
+import fs from 'fs';
+import {fileURLToPath} from 'node:url';
+import path from 'path';
 
+const dirname = path.dirname(fileURLToPath(import.meta.url));
 
 function clone(value) {
     return JSON.parse(JSON.stringify(value));
 }
 
 
-class ManifestUtil {
+export class ManifestUtil {
     constructor() {
-        const fileName = path.join(__dirname, 'data', 'manifest-variants.json');
+        const fileName = path.join(dirname, 'data', 'manifest-variants.json');
         const {manifest, variants, defaultVariant} = JSON.parse(fs.readFileSync(fileName));
         this._manifest = manifest;
         this._variants = variants;
@@ -74,7 +76,7 @@ class ManifestUtil {
     _evaluateModificationCommand(data) {
         const {command, args, trim} = data;
         const {stdout, stderr, status} = childProcess.spawnSync(command, args, {
-            cwd: __dirname,
+            cwd: dirname,
             stdio: 'pipe',
             shell: false
         });
@@ -263,7 +265,3 @@ class ManifestUtil {
     }
 }
 
-
-module.exports = {
-    ManifestUtil
-};
diff --git a/dev/patch-dependencies.js b/dev/patch-dependencies.js
deleted file mode 100644
index 81572c5c..00000000
--- a/dev/patch-dependencies.js
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * Copyright (C) 2023  Yomitan Authors
- * Copyright (C) 2021-2022  Yomichan Authors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-const fs = require('fs');
-const assert = require('assert');
-
-/**
- * This function patches the following bug:
- * - https://github.com/jsdom/jsdom/issues/3211
- * - https://github.com/dperini/nwsapi/issues/48
- */
-function patchNwsapi() {
-    const nwsapiPath = require.resolve('nwsapi');
-    const nwsapiSource = fs.readFileSync(nwsapiPath, {encoding: 'utf8'});
-    const pattern = /(if|while)(\()(?:e&&)?(\(e=e\.parentElement\)\)\{)/g;
-    let modifications = 0;
-    const nwsapiSourceNew = nwsapiSource.replace(pattern, (g0, g1, g2, g3) => {
-        ++modifications;
-        return `${g1}${g2}e&&${g3}`;
-    });
-    assert.strictEqual(modifications, 2);
-    fs.writeFileSync(nwsapiPath, nwsapiSourceNew, {encoding: 'utf8'});
-    // nwsapi is used by JSDOM
-    const {testJSDOM} = require('../test/test-jsdom');
-    testJSDOM();
-}
-
-function main() {
-    patchNwsapi();
-}
-
-if (require.main === module) { main(); }
diff --git a/dev/schema-validate.js b/dev/schema-validate.js
index 1d7607b7..fbd6b06a 100644
--- a/dev/schema-validate.js
+++ b/dev/schema-validate.js
@@ -16,21 +16,11 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-const fs = require('fs');
-const {performance} = require('perf_hooks');
-const {VM} = require('./vm');
-
-const vm = new VM();
-vm.execute([
-    'js/core.js',
-    'js/general/cache-map.js',
-    'js/data/json-schema.js'
-]);
-const JsonSchema = vm.get('JsonSchema');
+import Ajv from 'ajv';
+import {JsonSchema} from '../ext/js/data/json-schema.js';
 
 class JsonSchemaAjv {
     constructor(schema) {
-        const Ajv = require('ajv');
         const ajv = new Ajv({
             meta: false,
             strictTuples: false,
@@ -49,53 +39,9 @@ class JsonSchemaAjv {
     }
 }
 
-function createJsonSchema(mode, schema) {
+export function createJsonSchema(mode, schema) {
     switch (mode) {
         case 'ajv': return new JsonSchemaAjv(schema);
         default: return new JsonSchema(schema);
     }
 }
-
-function main() {
-    const args = process.argv.slice(2);
-    if (args.length < 2) {
-        console.log([
-            'Usage:',
-            '  node schema-validate [--ajv] <schema-file-name> <data-file-names>...'
-        ].join('\n'));
-        return;
-    }
-
-    let mode = null;
-    if (args[0] === '--ajv') {
-        mode = 'ajv';
-        args.splice(0, 1);
-    }
-
-    const schemaSource = fs.readFileSync(args[0], {encoding: 'utf8'});
-    const schema = JSON.parse(schemaSource);
-
-    for (const dataFileName of args.slice(1)) {
-        const start = performance.now();
-        try {
-            console.log(`Validating ${dataFileName}...`);
-            const dataSource = fs.readFileSync(dataFileName, {encoding: 'utf8'});
-            const data = JSON.parse(dataSource);
-            createJsonSchema(mode, schema).validate(data);
-            const end = performance.now();
-            console.log(`No issues detected (${((end - start) / 1000).toFixed(2)}s)`);
-        } catch (e) {
-            const end = performance.now();
-            console.log(`Encountered an error (${((end - start) / 1000).toFixed(2)}s)`);
-            console.warn(e);
-        }
-    }
-}
-
-
-if (require.main === module) { main(); }
-
-
-module.exports = {
-    createJsonSchema
-};
diff --git a/dev/translator-vm.js b/dev/translator-vm.js
index 2a51ab8c..9f14523e 100644
--- a/dev/translator-vm.js
+++ b/dev/translator-vm.js
@@ -16,19 +16,32 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-const fs = require('fs');
-const path = require('path');
-const assert = require('assert');
-const {DatabaseVM, DatabaseVMDictionaryImporterMediaLoader} = require('./database-vm');
-const {createDictionaryArchive} = require('./util');
-
-function clone(value) {
-    return JSON.parse(JSON.stringify(value));
-}
+import fs from 'fs';
+import url, {fileURLToPath} from 'node:url';
+import path from 'path';
+import {expect, vi} from 'vitest';
+import {AnkiNoteDataCreator} from '../ext/js/data/sandbox/anki-note-data-creator.js';
+import {DictionaryDatabase} from '../ext/js/language/dictionary-database.js';
+import {DictionaryImporterMediaLoader} from '../ext/js/language/dictionary-importer-media-loader.js';
+import {DictionaryImporter} from '../ext/js/language/dictionary-importer.js';
+import {JapaneseUtil} from '../ext/js/language/sandbox/japanese-util.js';
+import {Translator} from '../ext/js/language/translator.js';
+import {createDictionaryArchive} from './util.js';
+
+vi.mock('../ext/js/language/dictionary-importer-media-loader.js');
+
+const dirname = path.dirname(fileURLToPath(import.meta.url));
+
+export class TranslatorVM {
+    constructor() {
+        global.chrome = {
+            runtime: {
+                getURL: (path2) => {
+                    return url.pathToFileURL(path.join(dirname, '..', 'ext', path2.replace(/^\//, ''))).href;
+                }
+            }
+        };
 
-class TranslatorVM extends DatabaseVM {
-    constructor(globals) {
-        super(globals);
         this._japaneseUtil = null;
         this._translator = null;
         this._ankiNoteDataCreator = null;
@@ -40,43 +53,14 @@ class TranslatorVM extends DatabaseVM {
     }
 
     async prepare(dictionaryDirectory, dictionaryName) {
-        this.execute([
-            'js/core.js',
-            'js/data/sandbox/anki-note-data-creator.js',
-            'js/data/database.js',
-            'js/data/json-schema.js',
-            'js/general/cache-map.js',
-            'js/general/regex-util.js',
-            'js/general/text-source-map.js',
-            'js/language/deinflector.js',
-            'js/language/sandbox/dictionary-data-util.js',
-            'js/language/dictionary-importer.js',
-            'js/language/dictionary-database.js',
-            'js/language/sandbox/japanese-util.js',
-            'js/language/translator.js',
-            'js/media/media-util.js'
-        ]);
-        const [
-            DictionaryImporter,
-            DictionaryDatabase,
-            JapaneseUtil,
-            Translator,
-            AnkiNoteDataCreator
-        ] = this.get([
-            'DictionaryImporter',
-            'DictionaryDatabase',
-            'JapaneseUtil',
-            'Translator',
-            'AnkiNoteDataCreator'
-        ]);
-
         // Dictionary
         this._dictionaryName = dictionaryName;
         const testDictionary = createDictionaryArchive(dictionaryDirectory, dictionaryName);
+        // const testDictionaryContent = await testDictionary.arrayBuffer();
         const testDictionaryContent = await testDictionary.generateAsync({type: 'arraybuffer'});
 
         // Setup database
-        const dictionaryImporterMediaLoader = new DatabaseVMDictionaryImporterMediaLoader();
+        const dictionaryImporterMediaLoader = new DictionaryImporterMediaLoader();
         const dictionaryImporter = new DictionaryImporter(dictionaryImporterMediaLoader, null);
         const dictionaryDatabase = new DictionaryDatabase();
         await dictionaryDatabase.prepare();
@@ -87,7 +71,9 @@ class TranslatorVM extends DatabaseVM {
             {prefixWildcardsSupported: true}
         );
 
-        assert.deepStrictEqual(errors.length, 0);
+        expect(errors.length).toEqual(0);
+
+        const myDirname = path.dirname(fileURLToPath(import.meta.url));
 
         // Setup translator
         this._japaneseUtil = new JapaneseUtil(null);
@@ -95,7 +81,7 @@ class TranslatorVM extends DatabaseVM {
             japaneseUtil: this._japaneseUtil,
             database: dictionaryDatabase
         });
-        const deinflectionReasons = JSON.parse(fs.readFileSync(path.join(__dirname, '..', 'ext', 'data/deinflect.json')));
+        const deinflectionReasons = JSON.parse(fs.readFileSync(path.join(myDirname, '..', 'ext', 'data/deinflect.json')));
         this._translator.prepare(deinflectionReasons);
 
         // Assign properties
@@ -132,10 +118,10 @@ class TranslatorVM extends DatabaseVM {
                     if (!Object.prototype.hasOwnProperty.call(optionsPresets, entry)) {
                         throw new Error('Invalid options preset');
                     }
-                    Object.assign(options, clone(optionsPresets[entry]));
+                    Object.assign(options, structuredClone(optionsPresets[entry]));
                     break;
                 case 'object':
-                    Object.assign(options, clone(entry));
+                    Object.assign(options, structuredClone(entry));
                     break;
                 default:
                     throw new Error('Invalid options type');
@@ -177,7 +163,3 @@ class TranslatorVM extends DatabaseVM {
         return options;
     }
 }
-
-module.exports = {
-    TranslatorVM
-};
diff --git a/dev/util.js b/dev/util.js
index 65b1d982..cabc40aa 100644
--- a/dev/util.js
+++ b/dev/util.js
@@ -16,24 +16,11 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-const fs = require('fs');
-const path = require('path');
+import fs from 'fs';
+import JSZip from 'jszip';
+import path from 'path';
 
-
-let JSZip = null;
-
-
-function getJSZip() {
-    if (JSZip === null) {
-        process.noDeprecation = true; // Suppress a warning about JSZip
-        JSZip = require(path.join(__dirname, '../ext/lib/jszip.min.js'));
-        process.noDeprecation = false;
-    }
-    return JSZip;
-}
-
-
-function getArgs(args, argMap) {
+export function getArgs(args, argMap) {
     let key = null;
     let canKey = true;
     let onKey = false;
@@ -77,7 +64,7 @@ function getArgs(args, argMap) {
     return argMap;
 }
 
-function getAllFiles(baseDirectory, predicate=null) {
+export function getAllFiles(baseDirectory, predicate=null) {
     const results = [];
     const directories = [baseDirectory];
     while (directories.length > 0) {
@@ -99,11 +86,12 @@ function getAllFiles(baseDirectory, predicate=null) {
     return results;
 }
 
-function createDictionaryArchive(dictionaryDirectory, dictionaryName) {
+export function createDictionaryArchive(dictionaryDirectory, dictionaryName) {
     const fileNames = fs.readdirSync(dictionaryDirectory);
 
-    const JSZip2 = getJSZip();
-    const archive = new JSZip2();
+    // const zipFileWriter = new BlobWriter();
+    // const zipWriter = new ZipWriter(zipFileWriter);
+    const archive = new JSZip();
 
     for (const fileName of fileNames) {
         if (/\.json$/.test(fileName)) {
@@ -113,17 +101,31 @@ function createDictionaryArchive(dictionaryDirectory, dictionaryName) {
                 json.title = dictionaryName;
             }
             archive.file(fileName, JSON.stringify(json, null, 0));
+
+            // await zipWriter.add(fileName, new TextReader(JSON.stringify(json, null, 0)));
         } else {
             const content = fs.readFileSync(path.join(dictionaryDirectory, fileName), {encoding: null});
             archive.file(fileName, content);
+
+            // console.log('adding');
+            // const r = new TextReader(content);
+            // console.log(r.readUint8Array(0, 10));
+            // console.log('reader done');
+            // await zipWriter.add(fileName, r);
+            // console.log('??');
         }
     }
+    // await zipWriter.close();
 
+    // Retrieves the Blob object containing the zip content into `zipFileBlob`. It
+    // is also returned by zipWriter.close() for more convenience.
+    // const zipFileBlob = await zipFileWriter.getData();
     return archive;
-}
 
+    // return zipFileBlob;
+}
 
-async function testMain(func, ...args) {
+export async function testMain(func, ...args) {
     try {
         await func(...args);
     } catch (e) {
@@ -131,12 +133,3 @@ async function testMain(func, ...args) {
         process.exit(-1);
     }
 }
-
-
-module.exports = {
-    get JSZip() { return getJSZip(); },
-    getArgs,
-    getAllFiles,
-    createDictionaryArchive,
-    testMain
-};
diff --git a/dev/vm.js b/dev/vm.js
deleted file mode 100644
index c3266443..00000000
--- a/dev/vm.js
+++ /dev/null
@@ -1,204 +0,0 @@
-/*
- * Copyright (C) 2023  Yomitan Authors
- * Copyright (C) 2020-2022  Yomichan Authors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-const fs = require('fs');
-const vm = require('vm');
-const path = require('path');
-const assert = require('assert');
-const crypto = require('crypto');
-
-
-function getContextEnvironmentRecords(context, names) {
-    // Enables export of values from the declarative environment record
-    if (!Array.isArray(names) || names.length === 0) {
-        return [];
-    }
-
-    let scriptSource = '(() => {\n    "use strict";\n    const results = [];';
-    for (const name of names) {
-        scriptSource += `\n    try { results.push(${name}); } catch (e) { results.push(void 0); }`;
-    }
-    scriptSource += '\n    return results;\n})();';
-
-    const script = new vm.Script(scriptSource, {filename: 'getContextEnvironmentRecords'});
-
-    const contextHasNames = Object.prototype.hasOwnProperty.call(context, 'names');
-    const contextNames = context.names;
-    context.names = names;
-
-    const results = script.runInContext(context, {});
-
-    if (contextHasNames) {
-        context.names = contextNames;
-    } else {
-        delete context.names;
-    }
-
-    return Array.from(results);
-}
-
-function isDeepStrictEqual(val1, val2) {
-    if (val1 === val2) { return true; }
-
-    if (Array.isArray(val1)) {
-        if (Array.isArray(val2)) {
-            return isArrayDeepStrictEqual(val1, val2);
-        }
-    } else if (typeof val1 === 'object' && val1 !== null) {
-        if (typeof val2 === 'object' && val2 !== null) {
-            return isObjectDeepStrictEqual(val1, val2);
-        }
-    }
-
-    return false;
-}
-
-function isArrayDeepStrictEqual(val1, val2) {
-    const ii = val1.length;
-    if (ii !== val2.length) { return false; }
-
-    for (let i = 0; i < ii; ++i) {
-        if (!isDeepStrictEqual(val1[i], val2[i])) {
-            return false;
-        }
-    }
-
-    return true;
-}
-
-function isObjectDeepStrictEqual(val1, val2) {
-    const keys1 = Object.keys(val1);
-    const keys2 = Object.keys(val2);
-
-    if (keys1.length !== keys2.length) { return false; }
-
-    const keySet = new Set(keys1);
-    for (const key of keys2) {
-        if (!keySet.delete(key)) { return false; }
-    }
-
-    for (const key of keys1) {
-        if (!isDeepStrictEqual(val1[key], val2[key])) {
-            return false;
-        }
-    }
-
-    const tag1 = Object.prototype.toString.call(val1);
-    const tag2 = Object.prototype.toString.call(val2);
-    if (tag1 !== tag2) { return false; }
-
-    return true;
-}
-
-function deepStrictEqual(actual, expected) {
-    try {
-        // This will fail on prototype === comparison on cross context objects
-        assert.deepStrictEqual(actual, expected);
-    } catch (e) {
-        if (!isDeepStrictEqual(actual, expected)) {
-            throw e;
-        }
-    }
-}
-
-
-function createURLClass() {
-    const BaseURL = URL;
-    const result = function URL(url) {
-        const u = new BaseURL(url);
-        this.hash = u.hash;
-        this.host = u.host;
-        this.hostname = u.hostname;
-        this.href = u.href;
-        this.origin = u.origin;
-        this.password = u.password;
-        this.pathname = u.pathname;
-        this.port = u.port;
-        this.protocol = u.protocol;
-        this.search = u.search;
-        this.searchParams = u.searchParams;
-        this.username = u.username;
-    };
-    return result;
-}
-
-
-class VM {
-    constructor(context={}) {
-        context.URL = createURLClass();
-        context.crypto = {
-            getRandomValues: (array) => {
-                const buffer = crypto.randomBytes(array.byteLength);
-                buffer.copy(array);
-                return array;
-            }
-        };
-        this._context = vm.createContext(context);
-        this._assert = {
-            deepStrictEqual
-        };
-    }
-
-    get context() {
-        return this._context;
-    }
-
-    get assert() {
-        return this._assert;
-    }
-
-    get(names) {
-        if (typeof names === 'string') {
-            return getContextEnvironmentRecords(this._context, [names])[0];
-        } else if (Array.isArray(names)) {
-            return getContextEnvironmentRecords(this._context, names);
-        } else {
-            throw new Error('Invalid argument');
-        }
-    }
-
-    set(values) {
-        if (typeof values === 'object' && values !== null) {
-            Object.assign(this._context, values);
-        } else {
-            throw new Error('Invalid argument');
-        }
-    }
-
-    execute(fileNames) {
-        const single = !Array.isArray(fileNames);
-        if (single) {
-            fileNames = [fileNames];
-        }
-
-        const results = [];
-        for (const fileName of fileNames) {
-            const absoluteFileName = path.resolve(__dirname, '..', 'ext', fileName);
-            const source = fs.readFileSync(absoluteFileName, {encoding: 'utf8'});
-            const script = new vm.Script(source, {filename: absoluteFileName});
-            results.push(script.runInContext(this._context, {}));
-        }
-
-        return single ? results[0] : results;
-    }
-}
-
-
-module.exports = {
-    VM
-};