Move bg/js (#1387)

* Move bg/js/anki.js to js/comm/anki.js

* Move bg/js/mecab.js to js/comm/mecab.js

* Move bg/js/search-main.js to js/display/search-main.js

* Move bg/js/template-patcher.js to js/templates/template-patcher.js

* Move bg/js/template-renderer-frame-api.js to js/templates/template-renderer-frame-api.js

* Move bg/js/template-renderer-frame-main.js to js/templates/template-renderer-frame-main.js

* Move bg/js/template-renderer-proxy.js to js/templates/template-renderer-proxy.js

* Move bg/js/template-renderer.js to js/templates/template-renderer.js

* Move bg/js/media-utility.js to js/media/media-utility.js

* Move bg/js/native-simple-dom-parser.js to js/dom/native-simple-dom-parser.js

* Move bg/js/simple-dom-parser.js to js/dom/simple-dom-parser.js

* Move bg/js/audio-downloader.js to js/media/audio-downloader.js

* Move bg/js/deinflector.js to js/language/deinflector.js

* Move bg/js/backend.js to js/background/backend.js

* Move bg/js/translator.js to js/language/translator.js

* Move bg/js/search-display-controller.js to js/display/search-display-controller.js

* Move bg/js/request-builder.js to js/background/request-builder.js

* Move bg/js/text-source-map.js to js/general/text-source-map.js

* Move bg/js/clipboard-reader.js to js/comm/clipboard-reader.js

* Move bg/js/clipboard-monitor.js to js/comm/clipboard-monitor.js

* Move bg/js/query-parser.js to js/display/query-parser.js

* Move bg/js/profile-conditions.js to js/background/profile-conditions.js

* Move bg/js/dictionary-database.js to js/language/dictionary-database.js

* Move bg/js/dictionary-importer.js to js/language/dictionary-importer.js

* Move bg/js/anki-note-builder.js to js/data/anki-note-builder.js

* Move bg/js/anki-note-data.js to js/data/anki-note-data.js

* Move bg/js/database.js to js/data/database.js

* Move bg/js/json-schema.js to js/data/json-schema.js

* Move bg/js/options.js to js/data/options-util.js

* Move bg/js/background-main.js to js/background/background-main.js

* Move bg/js/permissions-util.js to js/data/permissions-util.js

* Move bg/js/context-main.js to js/pages/action-popup-main.js

* Move bg/js/generic-page-main.js to js/pages/generic-page-main.js

* Move bg/js/info-main.js to js/pages/info-main.js

* Move bg/js/permissions-main.js to js/pages/permissions-main.js

* Move bg/js/welcome-main.js to js/pages/welcome-main.js

5 files changed, 776 insertions, 0 deletions

diff --git a/ext/js/templates/template-patcher.js b/ext/js/templates/template-patcher.js
new file mode 100644
index 00000000..57178957
--- /dev/null
+++ b/ext/js/templates/template-patcher.js
@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2021  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/>.
+ */
+
+class TemplatePatcher {
+    constructor() {
+        this._diffPattern1 = /\n?\{\{<<<<<<<\}\}\n/g;
+        this._diffPattern2 = /\n\{\{=======\}\}\n/g;
+        this._diffPattern3 = /\n\{\{>>>>>>>\}\}\n*/g;
+        this._lookupMarkerPattern = /[ \t]*\{\{~?>\s*\(\s*lookup\s*\.\s*"marker"\s*\)\s*~?\}\}/g;
+    }
+
+    parsePatch(content) {
+        const diffPattern1 = this._diffPattern1;
+        const diffPattern2 = this._diffPattern2;
+        const diffPattern3 = this._diffPattern3;
+        const modifications = [];
+        let index = 0;
+
+        while (true) {
+            // Find modification boundaries
+            diffPattern1.lastIndex = index;
+            const m1 = diffPattern1.exec(content);
+            if (m1 === null) { break; }
+
+            diffPattern2.lastIndex = m1.index + m1[0].length;
+            const m2 = diffPattern2.exec(content);
+            if (m2 === null) { break; }
+
+            diffPattern3.lastIndex = m2.index + m2[0].length;
+            const m3 = diffPattern3.exec(content);
+            if (m3 === null) { break; }
+
+            // Construct
+            const current = content.substring(m1.index + m1[0].length, m2.index);
+            const replacement = content.substring(m2.index + m2[0].length, m3.index);
+
+            if (current.length > 0) {
+                modifications.push({current, replacement});
+            }
+
+            // Update
+            content = content.substring(0, m1.index) + content.substring(m3.index + m3[0].length);
+            index = m1.index;
+        }
+
+        return {addition: content, modifications};
+    }
+
+    applyPatch(template, patch) {
+        for (const {current, replacement} of patch.modifications) {
+            let fromIndex = 0;
+            while (true) {
+                const index = template.indexOf(current, fromIndex);
+                if (index < 0) { break; }
+                template = template.substring(0, index) + replacement + template.substring(index + current.length);
+                fromIndex = index + replacement.length;
+            }
+        }
+        template = this._addFieldTemplatesBeforeEnd(template, patch.addition);
+        return template;
+    }
+
+    // Private
+
+    _addFieldTemplatesBeforeEnd(template, addition) {
+        const newline = '\n';
+        let replaced = false;
+        template = template.replace(this._lookupMarkerPattern, (g0) => {
+            replaced = true;
+            return `${addition}${newline}${g0}`;
+        });
+        if (!replaced) {
+            template += newline;
+            template += addition;
+        }
+        return template;
+    }
+}
diff --git a/ext/js/templates/template-renderer-frame-api.js b/ext/js/templates/template-renderer-frame-api.js
new file mode 100644
index 00000000..4936a2af
--- /dev/null
+++ b/ext/js/templates/template-renderer-frame-api.js
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2020-2021  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/>.
+ */
+
+class TemplateRendererFrameApi {
+    constructor(templateRenderer) {
+        this._templateRenderer = templateRenderer;
+        this._windowMessageHandlers = new Map([
+            ['render', {async: true, handler: this._onRender.bind(this)}]
+        ]);
+    }
+
+    prepare() {
+        window.addEventListener('message', this._onWindowMessage.bind(this), false);
+    }
+
+    // Private
+
+    _onWindowMessage(e) {
+        const {source, data: {action, params, id}} = e;
+        const messageHandler = this._windowMessageHandlers.get(action);
+        if (typeof messageHandler === 'undefined') { return; }
+
+        this._onWindowMessageInner(messageHandler, action, params, source, id);
+    }
+
+    async _onWindowMessageInner({handler, async}, action, params, source, id) {
+        let response;
+        try {
+            let result = handler(params);
+            if (async) {
+                result = await result;
+            }
+            response = {result};
+        } catch (error) {
+            response = {error: this._errorToJson(error)};
+        }
+
+        if (typeof id === 'undefined') { return; }
+        source.postMessage({action: `${action}.response`, params: response, id}, '*');
+    }
+
+    async _onRender({template, data, type}) {
+        return await this._templateRenderer.render(template, data, type);
+    }
+
+    _errorToJson(error) {
+        try {
+            if (error !== null && typeof error === 'object') {
+                return {
+                    name: error.name,
+                    message: error.message,
+                    stack: error.stack,
+                    data: error.data
+                };
+            }
+        } catch (e) {
+            // NOP
+        }
+        return {
+            value: error,
+            hasValue: true
+        };
+    }
+}
diff --git a/ext/js/templates/template-renderer-frame-main.js b/ext/js/templates/template-renderer-frame-main.js
new file mode 100644
index 00000000..d25eb56d
--- /dev/null
+++ b/ext/js/templates/template-renderer-frame-main.js
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2020-2021  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/>.
+ */
+
+/* globals
+ * AnkiNoteData
+ * JapaneseUtil
+ * TemplateRenderer
+ * TemplateRendererFrameApi
+ */
+
+(() => {
+    const japaneseUtil = new JapaneseUtil(null);
+    const templateRenderer = new TemplateRenderer(japaneseUtil);
+    templateRenderer.registerDataType('ankiNote', {
+        modifier: ({data, marker}) => new AnkiNoteData(data, marker).createPublic()
+    });
+    const api = new TemplateRendererFrameApi(templateRenderer);
+    api.prepare();
+})();
diff --git a/ext/js/templates/template-renderer-proxy.js b/ext/js/templates/template-renderer-proxy.js
new file mode 100644
index 00000000..6a49832b
--- /dev/null
+++ b/ext/js/templates/template-renderer-proxy.js
@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2020-2021  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/>.
+ */
+
+class TemplateRendererProxy {
+    constructor() {
+        this._frame = null;
+        this._frameNeedsLoad = true;
+        this._frameLoading = false;
+        this._frameLoadPromise = null;
+        this._frameUrl = chrome.runtime.getURL('/template-renderer.html');
+        this._invocations = new Set();
+    }
+
+    async render(template, data, type) {
+        await this._prepareFrame();
+        return await this._invoke('render', {template, data, type});
+    }
+
+    // Private
+
+    async _prepareFrame() {
+        if (this._frame === null) {
+            this._frame = document.createElement('iframe');
+            this._frame.addEventListener('load', this._onFrameLoad.bind(this), false);
+            const style = this._frame.style;
+            style.opacity = '0';
+            style.width = '0';
+            style.height = '0';
+            style.position = 'absolute';
+            style.border = '0';
+            style.margin = '0';
+            style.padding = '0';
+            style.pointerEvents = 'none';
+        }
+        if (this._frameNeedsLoad) {
+            this._frameNeedsLoad = false;
+            this._frameLoading = true;
+            this._frameLoadPromise = this._loadFrame(this._frame, this._frameUrl)
+                .finally(() => { this._frameLoading = false; });
+        }
+        await this._frameLoadPromise;
+    }
+
+    _loadFrame(frame, url, timeout=5000) {
+        return new Promise((resolve, reject) => {
+            let ready = false;
+            const cleanup = () => {
+                frame.removeEventListener('load', onLoad, false);
+                if (timer !== null) {
+                    clearTimeout(timer);
+                    timer = null;
+                }
+            };
+            const onLoad = () => {
+                if (!ready) { return; }
+                cleanup();
+                resolve();
+            };
+
+            let timer = setTimeout(() => {
+                cleanup();
+                reject(new Error('Timeout'));
+            }, timeout);
+
+            frame.removeAttribute('src');
+            frame.removeAttribute('srcdoc');
+            frame.addEventListener('load', onLoad, false);
+            try {
+                document.body.appendChild(frame);
+                ready = true;
+                frame.contentDocument.location.href = url;
+            } catch (e) {
+                cleanup();
+                reject(e);
+            }
+        });
+    }
+
+    _invoke(action, params, timeout=null) {
+        return new Promise((resolve, reject) => {
+            const frameWindow = (this._frame !== null ? this._frame.contentWindow : null);
+            if (frameWindow === null) {
+                reject(new Error('Frame not set up'));
+                return;
+            }
+
+            const id = generateId(16);
+            const invocation = {
+                cancel: () => {
+                    cleanup();
+                    reject(new Error('Terminated'));
+                }
+            };
+
+            const cleanup = () => {
+                this._invocations.delete(invocation);
+                window.removeEventListener('message', onMessage, false);
+                if (timer !== null) {
+                    clearTimeout(timer);
+                    timer = null;
+                }
+            };
+            const onMessage = (e) => {
+                if (
+                    e.source !== frameWindow ||
+                    e.data.id !== id ||
+                    e.data.action !== `${action}.response`
+                ) {
+                    return;
+                }
+
+                const response = e.data.params;
+                cleanup();
+                const {error} = response;
+                if (error) {
+                    reject(deserializeError(error));
+                } else {
+                    resolve(response.result);
+                }
+            };
+
+            let timer = (typeof timeout === 'number' ? setTimeout(() => {
+                cleanup();
+                reject(new Error('Timeout'));
+            }, timeout) : null);
+
+            this._invocations.add(invocation);
+
+            window.addEventListener('message', onMessage, false);
+            frameWindow.postMessage({action, params, id}, '*');
+        });
+    }
+
+    _onFrameLoad() {
+        if (this._frameLoading) { return; }
+        this._frameNeedsLoad = true;
+
+        for (const invocation of this._invocations) {
+            invocation.cancel();
+        }
+        this._invocations.clear();
+    }
+}
diff --git a/ext/js/templates/template-renderer.js b/ext/js/templates/template-renderer.js
new file mode 100644
index 00000000..ae39e478
--- /dev/null
+++ b/ext/js/templates/template-renderer.js
@@ -0,0 +1,416 @@
+/*
+ * Copyright (C) 2016-2021  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/>.
+ */
+
+/* global
+ * Handlebars
+ */
+
+class TemplateRenderer {
+    constructor(japaneseUtil) {
+        this._japaneseUtil = japaneseUtil;
+        this._cache = new Map();
+        this._cacheMaxSize = 5;
+        this._helpersRegistered = false;
+        this._stateStack = null;
+        this._dataTypes = new Map();
+    }
+
+    registerDataType(name, {modifier=null, modifierPost=null}) {
+        this._dataTypes.set(name, {modifier, modifierPost});
+    }
+
+    async render(template, data, type) {
+        if (!this._helpersRegistered) {
+            this._registerHelpers();
+            this._helpersRegistered = true;
+        }
+
+        const cache = this._cache;
+        let instance = cache.get(template);
+        if (typeof instance === 'undefined') {
+            this._updateCacheSize(this._cacheMaxSize - 1);
+            instance = Handlebars.compile(template);
+            cache.set(template, instance);
+        }
+
+        let modifier = null;
+        let modifierPost = null;
+        if (typeof type === 'string') {
+            const typeInfo = this._dataTypes.get(type);
+            if (typeof typeInfo !== 'undefined') {
+                ({modifier, modifierPost} = typeInfo);
+            }
+        }
+
+        try {
+            if (typeof modifier === 'function') {
+                data = modifier(data);
+            }
+
+            this._stateStack = [new Map()];
+            return instance(data).trim();
+        } finally {
+            this._stateStack = null;
+
+            if (typeof modifierPost === 'function') {
+                modifierPost(data);
+            }
+        }
+    }
+
+    // Private
+
+    _updateCacheSize(maxSize) {
+        const cache = this._cache;
+        let removeCount = cache.size - maxSize;
+        if (removeCount <= 0) { return; }
+
+        for (const key of cache.keys()) {
+            cache.delete(key);
+            if (--removeCount <= 0) { break; }
+        }
+    }
+
+    _registerHelpers() {
+        Handlebars.partials = Handlebars.templates;
+
+        const helpers = [
+            ['dumpObject',       this._dumpObject.bind(this)],
+            ['furigana',         this._furigana.bind(this)],
+            ['furiganaPlain',    this._furiganaPlain.bind(this)],
+            ['kanjiLinks',       this._kanjiLinks.bind(this)],
+            ['multiLine',        this._multiLine.bind(this)],
+            ['sanitizeCssClass', this._sanitizeCssClass.bind(this)],
+            ['regexReplace',     this._regexReplace.bind(this)],
+            ['regexMatch',       this._regexMatch.bind(this)],
+            ['mergeTags',        this._mergeTags.bind(this)],
+            ['eachUpTo',         this._eachUpTo.bind(this)],
+            ['spread',           this._spread.bind(this)],
+            ['op',               this._op.bind(this)],
+            ['get',              this._get.bind(this)],
+            ['set',              this._set.bind(this)],
+            ['scope',            this._scope.bind(this)],
+            ['property',         this._property.bind(this)],
+            ['noop',             this._noop.bind(this)],
+            ['isMoraPitchHigh',  this._isMoraPitchHigh.bind(this)],
+            ['getKanaMorae',     this._getKanaMorae.bind(this)],
+            ['typeof',           this._getTypeof.bind(this)]
+        ];
+
+        for (const [name, helper] of helpers) {
+            this._registerHelper(name, helper);
+        }
+    }
+
+    _registerHelper(name, helper) {
+        function wrapper(...args) {
+            return helper(this, ...args);
+        }
+        Handlebars.registerHelper(name, wrapper);
+    }
+
+    _escape(text) {
+        return Handlebars.Utils.escapeExpression(text);
+    }
+
+    _dumpObject(context, options) {
+        const dump = JSON.stringify(options.fn(context), null, 4);
+        return this._escape(dump);
+    }
+
+    _furigana(context, ...args) {
+        const {expression, reading} = this._getFuriganaExpressionAndReading(context, ...args);
+        const segs = this._japaneseUtil.distributeFurigana(expression, reading);
+
+        let result = '';
+        for (const seg of segs) {
+            if (seg.furigana.length > 0) {
+                result += `<ruby>${seg.text}<rt>${seg.furigana}</rt></ruby>`;
+            } else {
+                result += seg.text;
+            }
+        }
+
+        return result;
+    }
+
+    _furiganaPlain(context, ...args) {
+        const {expression, reading} = this._getFuriganaExpressionAndReading(context, ...args);
+        const segs = this._japaneseUtil.distributeFurigana(expression, reading);
+
+        let result = '';
+        for (const seg of segs) {
+            if (seg.furigana.length > 0) {
+                if (result.length > 0) { result += ' '; }
+                result += `${seg.text}[${seg.furigana}]`;
+            } else {
+                result += seg.text;
+            }
+        }
+
+        return result;
+    }
+
+    _getFuriganaExpressionAndReading(context, ...args) {
+        const options = args[args.length - 1];
+        if (args.length >= 3) {
+            return {expression: args[0], reading: args[1]};
+        } else {
+            const {expression, reading} = options.fn(context);
+            return {expression, reading};
+        }
+    }
+
+    _kanjiLinks(context, options) {
+        const jp = this._japaneseUtil;
+        let result = '';
+        for (const c of options.fn(context)) {
+            if (jp.isCodePointKanji(c.codePointAt(0))) {
+                result += `<a href="#" class="kanji-link">${c}</a>`;
+            } else {
+                result += c;
+            }
+        }
+
+        return result;
+    }
+
+    _multiLine(context, options) {
+        return options.fn(context).split('\n').join('<br>');
+    }
+
+    _sanitizeCssClass(context, options) {
+        return options.fn(context).replace(/[^_a-z0-9\u00a0-\uffff]/ig, '_');
+    }
+
+    _regexReplace(context, ...args) {
+        // Usage:
+        // {{#regexReplace regex string [flags]}}content{{/regexReplace}}
+        // regex: regular expression string
+        // string: string to replace
+        // flags: optional flags for regular expression
+        //   e.g. "i" for case-insensitive, "g" for replace all
+        let value = args[args.length - 1].fn(context);
+        if (args.length >= 3) {
+            try {
+                const flags = args.length > 3 ? args[2] : 'g';
+                const regex = new RegExp(args[0], flags);
+                value = value.replace(regex, args[1]);
+            } catch (e) {
+                return `${e}`;
+            }
+        }
+        return value;
+    }
+
+    _regexMatch(context, ...args) {
+        // Usage:
+        // {{#regexMatch regex [flags]}}content{{/regexMatch}}
+        // regex: regular expression string
+        // flags: optional flags for regular expression
+        //   e.g. "i" for case-insensitive, "g" for match all
+        let value = args[args.length - 1].fn(context);
+        if (args.length >= 2) {
+            try {
+                const flags = args.length > 2 ? args[1] : '';
+                const regex = new RegExp(args[0], flags);
+                const parts = [];
+                value.replace(regex, (g0) => parts.push(g0));
+                value = parts.join('');
+            } catch (e) {
+                return `${e}`;
+            }
+        }
+        return value;
+    }
+
+    _mergeTags(context, object, isGroupMode, isMergeMode) {
+        const tagSources = [];
+        if (isGroupMode || isMergeMode) {
+            for (const definition of object.definitions) {
+                tagSources.push(definition.definitionTags);
+            }
+        } else {
+            tagSources.push(object.definitionTags);
+        }
+
+        const tags = new Set();
+        for (const tagSource of tagSources) {
+            for (const tag of tagSource) {
+                tags.add(tag.name);
+            }
+        }
+
+        return [...tags].join(', ');
+    }
+
+    _eachUpTo(context, iterable, maxCount, options) {
+        if (iterable) {
+            const results = [];
+            let any = false;
+            for (const entry of iterable) {
+                any = true;
+                if (results.length >= maxCount) { break; }
+                const processedEntry = options.fn(entry);
+                results.push(processedEntry);
+            }
+            if (any) {
+                return results.join('');
+            }
+        }
+        return options.inverse(context);
+    }
+
+    _spread(context, ...args) {
+        const result = [];
+        for (let i = 0, ii = args.length - 1; i < ii; ++i) {
+            try {
+                result.push(...args[i]);
+            } catch (e) {
+                // NOP
+            }
+        }
+        return result;
+    }
+
+    _op(context, ...args) {
+        switch (args.length) {
+            case 3: return this._evaluateUnaryExpression(args[0], args[1]);
+            case 4: return this._evaluateBinaryExpression(args[0], args[1], args[2]);
+            case 5: return this._evaluateTernaryExpression(args[0], args[1], args[2], args[3]);
+            default: return void 0;
+        }
+    }
+
+    _evaluateUnaryExpression(operator, operand1) {
+        switch (operator) {
+            case '+': return +operand1;
+            case '-': return -operand1;
+            case '~': return ~operand1;
+            case '!': return !operand1;
+            default: return void 0;
+        }
+    }
+
+    _evaluateBinaryExpression(operator, operand1, operand2) {
+        switch (operator) {
+            case '+': return operand1 + operand2;
+            case '-': return operand1 - operand2;
+            case '/': return operand1 / operand2;
+            case '*': return operand1 * operand2;
+            case '%': return operand1 % operand2;
+            case '**': return operand1 ** operand2;
+            case '==': return operand1 == operand2; // eslint-disable-line eqeqeq
+            case '!=': return operand1 != operand2; // eslint-disable-line eqeqeq
+            case '===': return operand1 === operand2;
+            case '!==': return operand1 !== operand2;
+            case '<':  return operand1 < operand2;
+            case '<=': return operand1 <= operand2;
+            case '>':  return operand1 > operand2;
+            case '>=': return operand1 >= operand2;
+            case '<<': return operand1 << operand2;
+            case '>>': return operand1 >> operand2;
+            case '>>>': return operand1 >>> operand2;
+            case '&': return operand1 & operand2;
+            case '|': return operand1 | operand2;
+            case '^': return operand1 ^ operand2;
+            case '&&': return operand1 && operand2;
+            case '||': return operand1 || operand2;
+            default: return void 0;
+        }
+    }
+
+    _evaluateTernaryExpression(operator, operand1, operand2, operand3) {
+        switch (operator) {
+            case '?:': return operand1 ? operand2 : operand3;
+            default: return void 0;
+        }
+    }
+
+    _get(context, key) {
+        for (let i = this._stateStack.length; --i >= 0;) {
+            const map = this._stateStack[i];
+            if (map.has(key)) {
+                return map.get(key);
+            }
+        }
+        return void 0;
+    }
+
+    _set(context, ...args) {
+        switch (args.length) {
+            case 2:
+                {
+                    const [key, options] = args;
+                    const value = options.fn(context);
+                    this._stateStack[this._stateStack.length - 1].set(key, value);
+                }
+                break;
+            case 3:
+                {
+                    const [key, value] = args;
+                    this._stateStack[this._stateStack.length - 1].set(key, value);
+                }
+                break;
+        }
+        return '';
+    }
+
+    _scope(context, options) {
+        try {
+            this._stateStack.push(new Map());
+            return options.fn(context);
+        } finally {
+            if (this._stateStack.length > 1) {
+                this._stateStack.pop();
+            }
+        }
+    }
+
+    _property(context, ...args) {
+        const ii = args.length - 1;
+        if (ii <= 0) { return void 0; }
+
+        try {
+            let value = args[0];
+            for (let i = 1; i < ii; ++i) {
+                value = value[args[i]];
+            }
+            return value;
+        } catch (e) {
+            return void 0;
+        }
+    }
+
+    _noop(context, options) {
+        return options.fn(context);
+    }
+
+    _isMoraPitchHigh(context, index, position) {
+        return this._japaneseUtil.isMoraPitchHigh(index, position);
+    }
+
+    _getKanaMorae(context, text) {
+        return this._japaneseUtil.getKanaMorae(`${text}`);
+    }
+
+    _getTypeof(context, ...args) {
+        const ii = args.length - 1;
+        const value = (ii > 0 ? args[0] : args[ii].fn(context));
+        return typeof value;
+    }
+}