IIFE updates (#384)

* Remove most IIFEs

* Move IIFEs into functions

* Don't await background-main

17 files changed, 288 insertions, 267 deletions

diff --git a/ext/js/app/content-script-main.js b/ext/js/app/content-script-main.js
index 972d032c..7b76fda0 100644
--- a/ext/js/app/content-script-main.js
+++ b/ext/js/app/content-script-main.js
@@ -22,7 +22,8 @@ import {yomitan} from '../yomitan.js';
 import {Frontend} from './frontend.js';
 import {PopupFactory} from './popup-factory.js';
 
-(async () => {
+/** Entry point. */
+async function main() {
     try {
         await yomitan.prepare();
 
@@ -57,4 +58,6 @@ import {PopupFactory} from './popup-factory.js';
     } catch (e) {
         log.error(e);
     }
-})();
+}
+
+await main();
diff --git a/ext/js/background/background-main.js b/ext/js/background/background-main.js
index 8e32a53f..29c256d3 100644
--- a/ext/js/background/background-main.js
+++ b/ext/js/background/background-main.js
@@ -19,9 +19,12 @@
 import {yomitan} from '../yomitan.js';
 import {Backend} from './backend.js';
 
-(() => {
+/** Entry point. */
+async function main() {
     yomitan.prepare(true);
 
     const backend = new Backend();
-    backend.prepare();
-})();
+    await backend.prepare();
+}
+
+main();
diff --git a/ext/js/background/offscreen-main.js b/ext/js/background/offscreen-main.js
index dcbf978f..f85908bd 100644
--- a/ext/js/background/offscreen-main.js
+++ b/ext/js/background/offscreen-main.js
@@ -18,6 +18,9 @@
 
 import {Offscreen} from './offscreen.js';
 
-(() => {
+/** Entry point. */
+async function main() {
     new Offscreen();
-})();
+}
+
+await main();
diff --git a/ext/js/core.js b/ext/js/core.js
index 5c0c964b..c95eae01 100644
--- a/ext/js/core.js
+++ b/ext/js/core.js
@@ -53,101 +53,91 @@ export function stringReverse(string) {
  * @returns {T} A new clone of the value.
  * @throws An error if the value is circular and cannot be cloned.
  */
-export const clone = (() => {
-    /**
-     * @template T
-     * @param {T} value
-     * @returns {T}
-     */
-    // eslint-disable-next-line no-shadow, @typescript-eslint/no-shadow
-    function clone(value) {
-        if (value === null) { return /** @type {T} */ (null); }
-        switch (typeof value) {
-            case 'boolean':
-            case 'number':
-            case 'string':
-            case 'bigint':
-            case 'symbol':
-            case 'undefined':
-                return value;
-            default:
-                return cloneInternal(value, new Set());
-        }
+export function clone(value) {
+    if (value === null) { return /** @type {T} */ (null); }
+    switch (typeof value) {
+        case 'boolean':
+        case 'number':
+        case 'string':
+        case 'bigint':
+        case 'symbol':
+        case 'undefined':
+            return value;
+        default:
+            return cloneInternal(value, new Set());
     }
+}
 
-    /**
-     * @template [T=unknown]
-     * @param {T} value
-     * @param {Set<unknown>} visited
-     * @returns {T}
-     * @throws {Error}
-     */
-    function cloneInternal(value, visited) {
-        if (value === null) { return /** @type {T} */ (null); }
-        switch (typeof value) {
-            case 'boolean':
-            case 'number':
-            case 'string':
-            case 'bigint':
-            case 'symbol':
-            case 'undefined':
-                return value;
-            case 'object':
-                return /** @type {T} */ (
+/**
+ * @template [T=unknown]
+ * @param {T} value
+ * @param {Set<unknown>} visited
+ * @returns {T}
+ * @throws {Error}
+ */
+function cloneInternal(value, visited) {
+    if (value === null) { return /** @type {T} */ (null); }
+    switch (typeof value) {
+        case 'boolean':
+        case 'number':
+        case 'string':
+        case 'bigint':
+        case 'symbol':
+        case 'undefined':
+            return value;
+        case 'object':
+            return /** @type {T} */ (
                     Array.isArray(value) ?
                     cloneArray(value, visited) :
                     cloneObject(/** @type {import('core').SerializableObject} */ (value), visited)
-                );
-            default:
-                throw new Error(`Cannot clone object of type ${typeof value}`);
-        }
+            );
+        default:
+            throw new Error(`Cannot clone object of type ${typeof value}`);
     }
+}
 
-    /**
-     * @param {unknown[]} value
-     * @param {Set<unknown>} visited
-     * @returns {unknown[]}
-     * @throws {Error}
-     */
-    function cloneArray(value, visited) {
-        if (visited.has(value)) { throw new Error('Circular'); }
-        try {
-            visited.add(value);
-            const result = [];
-            for (const item of value) {
-                result.push(cloneInternal(item, visited));
-            }
-            return result;
-        } finally {
-            visited.delete(value);
+/**
+ * @param {unknown[]} value
+ * @param {Set<unknown>} visited
+ * @returns {unknown[]}
+ * @throws {Error}
+ */
+function cloneArray(value, visited) {
+    if (visited.has(value)) { throw new Error('Circular'); }
+    try {
+        visited.add(value);
+        const result = [];
+        for (const item of value) {
+            result.push(cloneInternal(item, visited));
         }
+        return result;
+    } finally {
+        visited.delete(value);
     }
+}
 
-    /**
-     * @param {import('core').SerializableObject} value
-     * @param {Set<unknown>} visited
-     * @returns {import('core').SerializableObject}
-     * @throws {Error}
-     */
-    function cloneObject(value, visited) {
-        if (visited.has(value)) { throw new Error('Circular'); }
-        try {
-            visited.add(value);
-            /** @type {import('core').SerializableObject} */
-            const result = {};
-            for (const key in value) {
-                if (Object.prototype.hasOwnProperty.call(value, key)) {
-                    result[key] = cloneInternal(value[key], visited);
-                }
+/**
+ * @param {import('core').SerializableObject} value
+ * @param {Set<unknown>} visited
+ * @returns {import('core').SerializableObject}
+ * @throws {Error}
+ */
+function cloneObject(value, visited) {
+    if (visited.has(value)) { throw new Error('Circular'); }
+    try {
+        visited.add(value);
+        /** @type {import('core').SerializableObject} */
+        const result = {};
+        for (const key in value) {
+            if (Object.prototype.hasOwnProperty.call(value, key)) {
+                result[key] = cloneInternal(value[key], visited);
             }
-            return result;
-        } finally {
-            visited.delete(value);
         }
+        return result;
+    } finally {
+        visited.delete(value);
     }
-
-    return clone;
-})();
+}
 
 /**
  * Checks if an object or value is deeply equal to another object or value.
@@ -155,98 +145,88 @@ export const clone = (() => {
  * @param {unknown} value2 The second value to check.
  * @returns {boolean} `true` if the values are the same object, or deeply equal without cycles. `false` otherwise.
  */
-export const deepEqual = (() => {
-    /**
-     * @param {unknown} value1
-     * @param {unknown} value2
-     * @returns {boolean}
-     */
-    // eslint-disable-next-line no-shadow, @typescript-eslint/no-shadow
-    function deepEqual(value1, value2) {
-        if (value1 === value2) { return true; }
-
-        const type = typeof value1;
-        if (typeof value2 !== type) { return false; }
-
-        switch (type) {
-            case 'object':
-            case 'function':
-                return deepEqualInternal(value1, value2, new Set());
-            default:
-                return false;
-        }
+export function deepEqual(value1, value2) {
+    if (value1 === value2) { return true; }
+
+    const type = typeof value1;
+    if (typeof value2 !== type) { return false; }
+
+    switch (type) {
+        case 'object':
+        case 'function':
+            return deepEqualInternal(value1, value2, new Set());
+        default:
+            return false;
     }
+}
 
-    /**
-     * @param {unknown} value1
-     * @param {unknown} value2
-     * @param {Set<unknown>} visited1
-     * @returns {boolean}
-     */
-    function deepEqualInternal(value1, value2, visited1) {
-        if (value1 === value2) { return true; }
-
-        const type = typeof value1;
-        if (typeof value2 !== type) { return false; }
-
-        switch (type) {
-            case 'object':
-            case 'function':
-            {
-                if (value1 === null || value2 === null) { return false; }
-                const array = Array.isArray(value1);
-                if (array !== Array.isArray(value2)) { return false; }
-                if (visited1.has(value1)) { return false; }
-                visited1.add(value1);
-                return (
+/**
+ * @param {unknown} value1
+ * @param {unknown} value2
+ * @param {Set<unknown>} visited1
+ * @returns {boolean}
+ */
+function deepEqualInternal(value1, value2, visited1) {
+    if (value1 === value2) { return true; }
+
+    const type = typeof value1;
+    if (typeof value2 !== type) { return false; }
+
+    switch (type) {
+        case 'object':
+        case 'function':
+        {
+            if (value1 === null || value2 === null) { return false; }
+            const array = Array.isArray(value1);
+            if (array !== Array.isArray(value2)) { return false; }
+            if (visited1.has(value1)) { return false; }
+            visited1.add(value1);
+            return (
                     array ?
                     areArraysEqual(/** @type {unknown[]} */ (value1), /** @type {unknown[]} */ (value2), visited1) :
                     areObjectsEqual(/** @type {import('core').UnknownObject} */ (value1), /** @type {import('core').UnknownObject} */ (value2), visited1)
-                );
-            }
-            default:
-                return false;
+            );
         }
+        default:
+            return false;
     }
+}
 
-    /**
-     * @param {import('core').UnknownObject} value1
-     * @param {import('core').UnknownObject} value2
-     * @param {Set<unknown>} visited1
-     * @returns {boolean}
-     */
-    function areObjectsEqual(value1, value2, visited1) {
-        const keys1 = Object.keys(value1);
-        const keys2 = Object.keys(value2);
-        if (keys1.length !== keys2.length) { return false; }
-
-        const keys1Set = new Set(keys1);
-        for (const key of keys2) {
-            if (!keys1Set.has(key) || !deepEqualInternal(value1[key], value2[key], visited1)) { return false; }
-        }
+/**
+ * @param {import('core').UnknownObject} value1
+ * @param {import('core').UnknownObject} value2
+ * @param {Set<unknown>} visited1
+ * @returns {boolean}
+ */
+function areObjectsEqual(value1, value2, visited1) {
+    const keys1 = Object.keys(value1);
+    const keys2 = Object.keys(value2);
+    if (keys1.length !== keys2.length) { return false; }
 
-        return true;
+    const keys1Set = new Set(keys1);
+    for (const key of keys2) {
+        if (!keys1Set.has(key) || !deepEqualInternal(value1[key], value2[key], visited1)) { return false; }
     }
 
-    /**
-     * @param {unknown[]} value1
-     * @param {unknown[]} value2
-     * @param {Set<unknown>} visited1
-     * @returns {boolean}
-     */
-    function areArraysEqual(value1, value2, visited1) {
-        const length = value1.length;
-        if (length !== value2.length) { return false; }
+    return true;
+}
 
-        for (let i = 0; i < length; ++i) {
-            if (!deepEqualInternal(value1[i], value2[i], visited1)) { return false; }
-        }
+/**
+ * @param {unknown[]} value1
+ * @param {unknown[]} value2
+ * @param {Set<unknown>} visited1
+ * @returns {boolean}
+ */
+function areArraysEqual(value1, value2, visited1) {
+    const length = value1.length;
+    if (length !== value2.length) { return false; }
 
-        return true;
+    for (let i = 0; i < length; ++i) {
+        if (!deepEqualInternal(value1[i], value2[i], visited1)) { return false; }
     }
 
-    return deepEqual;
-})();
+    return true;
+}
 
 /**
  * Creates a new base-16 (lower case) string of a sequence of random bytes of the given length.
diff --git a/ext/js/display/popup-main.js b/ext/js/display/popup-main.js
index 6b07b63f..fdb95508 100644
--- a/ext/js/display/popup-main.js
+++ b/ext/js/display/popup-main.js
@@ -27,7 +27,8 @@ import {DisplayProfileSelection} from './display-profile-selection.js';
 import {DisplayResizer} from './display-resizer.js';
 import {Display} from './display.js';
 
-(async () => {
+/** Entry point. */
+async function main() {
     try {
         const documentFocusController = new DocumentFocusController();
         documentFocusController.prepare();
@@ -64,4 +65,6 @@ import {Display} from './display.js';
     } catch (e) {
         log.error(e);
     }
-})();
+}
+
+await main();
diff --git a/ext/js/display/search-main.js b/ext/js/display/search-main.js
index 5eee08d1..fae7306a 100644
--- a/ext/js/display/search-main.js
+++ b/ext/js/display/search-main.js
@@ -29,7 +29,8 @@ import {SearchActionPopupController} from './search-action-popup-controller.js';
 import {SearchDisplayController} from './search-display-controller.js';
 import {SearchPersistentStateController} from './search-persistent-state-controller.js';
 
-(async () => {
+/** Entry point. */
+async function main() {
     try {
         const documentFocusController = new DocumentFocusController('#search-textbox');
         documentFocusController.prepare();
@@ -69,4 +70,6 @@ import {SearchPersistentStateController} from './search-persistent-state-control
     } catch (e) {
         log.error(e);
     }
-})();
+}
+
+await main();
diff --git a/ext/js/language/dictionary-worker-main.js b/ext/js/language/dictionary-worker-main.js
index 6d2386aa..8ae283b8 100644
--- a/ext/js/language/dictionary-worker-main.js
+++ b/ext/js/language/dictionary-worker-main.js
@@ -19,11 +19,14 @@
 import {log} from '../core.js';
 import {DictionaryWorkerHandler} from './dictionary-worker-handler.js';
 
-(() => {
+/** Entry point. */
+function main() {
     try {
         const dictionaryWorkerHandler = new DictionaryWorkerHandler();
         dictionaryWorkerHandler.prepare();
     } catch (e) {
         log.error(e);
     }
-})();
+}
+
+main();
diff --git a/ext/js/language/sandbox/japanese-util.js b/ext/js/language/sandbox/japanese-util.js
index 9d36497a..7d9413a6 100644
--- a/ext/js/language/sandbox/japanese-util.js
+++ b/ext/js/language/sandbox/japanese-util.js
@@ -161,32 +161,26 @@ const VOWEL_TO_KANA_MAPPING = new Map([
     ['', 'のノ']
 ]);
 
-const KANA_TO_VOWEL_MAPPING = (() => {
-    /** @type {Map<string, string>} */
-    const map = new Map();
-    for (const [vowel, characters] of VOWEL_TO_KANA_MAPPING) {
-        for (const character of characters) {
-            map.set(character, vowel);
-        }
+/** @type {Map<string, string>} */
+const KANA_TO_VOWEL_MAPPING = new Map();
+for (const [vowel, characters] of VOWEL_TO_KANA_MAPPING) {
+    for (const character of characters) {
+        KANA_TO_VOWEL_MAPPING.set(character, vowel);
     }
-    return map;
-})();
-
-const DIACRITIC_MAPPING = (() => {
-    const kana = 'うゔ-かが-きぎ-くぐ-けげ-こご-さざ-しじ-すず-せぜ-そぞ-ただ-ちぢ-つづ-てで-とど-はばぱひびぴふぶぷへべぺほぼぽワヷ-ヰヸ-ウヴ-ヱヹ-ヲヺ-カガ-キギ-クグ-ケゲ-コゴ-サザ-シジ-スズ-セゼ-ソゾ-タダ-チヂ-ツヅ-テデ-トド-ハバパヒビピフブプヘベペホボポ';
-    /** @type {Map<string, {character: string, type: import('japanese-util').DiacriticType}>} */
-    const map = new Map();
-    for (let i = 0, ii = kana.length; i < ii; i += 3) {
-        const character = kana[i];
-        const dakuten = kana[i + 1];
-        const handakuten = kana[i + 2];
-        map.set(dakuten, {character, type: 'dakuten'});
-        if (handakuten !== '-') {
-            map.set(handakuten, {character, type: 'handakuten'});
-        }
+}
+
+const kana = 'うゔ-かが-きぎ-くぐ-けげ-こご-さざ-しじ-すず-せぜ-そぞ-ただ-ちぢ-つづ-てで-とど-はばぱひびぴふぶぷへべぺほぼぽワヷ-ヰヸ-ウヴ-ヱヹ-ヲヺ-カガ-キギ-クグ-ケゲ-コゴ-サザ-シジ-スズ-セゼ-ソゾ-タダ-チヂ-ツヅ-テデ-トド-ハバパヒビピフブプヘベペホボポ';
+/** @type {Map<string, {character: string, type: import('japanese-util').DiacriticType}>} */
+const DIACRITIC_MAPPING = new Map();
+for (let i = 0, ii = kana.length; i < ii; i += 3) {
+    const character = kana[i];
+    const dakuten = kana[i + 1];
+    const handakuten = kana[i + 2];
+    DIACRITIC_MAPPING.set(dakuten, {character, type: 'dakuten'});
+    if (handakuten !== '-') {
+        DIACRITIC_MAPPING.set(handakuten, {character, type: 'handakuten'});
     }
-    return map;
-})();
+}
 
 
 /**
diff --git a/ext/js/pages/action-popup-main.js b/ext/js/pages/action-popup-main.js
index f8dd865f..9f72cc82 100644
--- a/ext/js/pages/action-popup-main.js
+++ b/ext/js/pages/action-popup-main.js
@@ -21,7 +21,7 @@ import {querySelectorNotNull} from '../dom/query-selector.js';
 import {HotkeyHelpController} from '../input/hotkey-help-controller.js';
 import {yomitan} from '../yomitan.js';
 
-export class DisplayController {
+class DisplayController {
     constructor() {
         /** @type {?import('settings').Options} */
         this._optionsFull = null;
@@ -302,7 +302,8 @@ export class DisplayController {
     }
 }
 
-(async () => {
+/** Entry point. */
+async function main() {
     await yomitan.prepare();
 
     yomitan.api.logIndicatorClear();
@@ -311,4 +312,6 @@ export class DisplayController {
     displayController.prepare();
 
     yomitan.ready();
-})();
+}
+
+await main();
diff --git a/ext/js/pages/generic-page-main.js b/ext/js/pages/generic-page-main.js
index 176537ae..4bb4c7ac 100644
--- a/ext/js/pages/generic-page-main.js
+++ b/ext/js/pages/generic-page-main.js
@@ -19,7 +19,8 @@
 import {DocumentFocusController} from '../dom/document-focus-controller.js';
 import {ExtensionContentController} from './common/extension-content-controller.js';
 
-(() => {
+/** Entry point. */
+function main() {
     const documentFocusController = new DocumentFocusController();
     documentFocusController.prepare();
 
@@ -27,4 +28,6 @@ import {ExtensionContentController} from './common/extension-content-controller.
     extensionContentController.prepare();
 
     document.documentElement.dataset.loaded = 'true';
-})();
+}
+
+main();
diff --git a/ext/js/pages/info-main.js b/ext/js/pages/info-main.js
index 7445354f..593b7460 100644
--- a/ext/js/pages/info-main.js
+++ b/ext/js/pages/info-main.js
@@ -56,7 +56,63 @@ function getOperatingSystemDisplayName(os) {
     }
 }
 
-(async () => {
+/** */
+async function showAnkiConnectInfo() {
+    let ankiConnectVersion = null;
+    try {
+        ankiConnectVersion = await yomitan.api.getAnkiConnectVersion();
+    } catch (e) {
+        // NOP
+    }
+
+    /** @type {HTMLElement} */
+    const ankiVersionElement = querySelectorNotNull(document, '#anki-connect-version');
+    /** @type {HTMLElement} */
+    const ankiVersionContainerElement = querySelectorNotNull(document, '#anki-connect-version-container');
+    /** @type {HTMLElement} */
+    const ankiVersionUnknownElement = querySelectorNotNull(document, '#anki-connect-version-unknown-message');
+
+    ankiVersionElement.textContent = (ankiConnectVersion !== null ? `${ankiConnectVersion}` : 'Unknown');
+    ankiVersionContainerElement.dataset.hasError = `${ankiConnectVersion === null}`;
+    ankiVersionUnknownElement.hidden = (ankiConnectVersion !== null);
+}
+
+/** */
+async function showDictionaryInfo() {
+    let dictionaryInfos;
+    try {
+        dictionaryInfos = await yomitan.api.getDictionaryInfo();
+    } catch (e) {
+        return;
+    }
+
+    const fragment = document.createDocumentFragment();
+    let first = true;
+    for (const {title} of dictionaryInfos) {
+        if (first) {
+            first = false;
+        } else {
+            fragment.appendChild(document.createTextNode(', '));
+        }
+
+        const node = document.createElement('span');
+        node.className = 'installed-dictionary';
+        node.textContent = title;
+        fragment.appendChild(node);
+    }
+
+    /** @type {HTMLElement} */
+    const noneElement = querySelectorNotNull(document, '#installed-dictionaries-none');
+
+    noneElement.hidden = (dictionaryInfos.length !== 0);
+    /** @type {HTMLElement} */
+    const container = querySelectorNotNull(document, '#installed-dictionaries');
+    container.textContent = '';
+    container.appendChild(fragment);
+}
+
+/** Entry point. */
+async function main() {
     try {
         const documentFocusController = new DocumentFocusController();
         documentFocusController.prepare();
@@ -92,58 +148,8 @@ function getOperatingSystemDisplayName(os) {
         languageElement.textContent = `${language}`;
         userAgentElement.textContent = userAgent;
 
-        (async () => {
-            let ankiConnectVersion = null;
-            try {
-                ankiConnectVersion = await yomitan.api.getAnkiConnectVersion();
-            } catch (e) {
-                // NOP
-            }
-
-            /** @type {HTMLElement} */
-            const ankiVersionElement = querySelectorNotNull(document, '#anki-connect-version');
-            /** @type {HTMLElement} */
-            const ankiVersionContainerElement = querySelectorNotNull(document, '#anki-connect-version-container');
-            /** @type {HTMLElement} */
-            const ankiVersionUnknownElement = querySelectorNotNull(document, '#anki-connect-version-unknown-message');
-
-            ankiVersionElement.textContent = (ankiConnectVersion !== null ? `${ankiConnectVersion}` : 'Unknown');
-            ankiVersionContainerElement.dataset.hasError = `${ankiConnectVersion === null}`;
-            ankiVersionUnknownElement.hidden = (ankiConnectVersion !== null);
-        })();
-
-        (async () => {
-            let dictionaryInfos;
-            try {
-                dictionaryInfos = await yomitan.api.getDictionaryInfo();
-            } catch (e) {
-                return;
-            }
-
-            const fragment = document.createDocumentFragment();
-            let first = true;
-            for (const {title} of dictionaryInfos) {
-                if (first) {
-                    first = false;
-                } else {
-                    fragment.appendChild(document.createTextNode(', '));
-                }
-
-                const node = document.createElement('span');
-                node.className = 'installed-dictionary';
-                node.textContent = title;
-                fragment.appendChild(node);
-            }
-
-            /** @type {HTMLElement} */
-            const noneElement = querySelectorNotNull(document, '#installed-dictionaries-none');
-
-            noneElement.hidden = (dictionaryInfos.length !== 0);
-            /** @type {HTMLElement} */
-            const container = querySelectorNotNull(document, '#installed-dictionaries');
-            container.textContent = '';
-            container.appendChild(fragment);
-        })();
+        showAnkiConnectInfo();
+        showDictionaryInfo();
 
         const settingsController = new SettingsController();
         await settingsController.prepare();
@@ -157,4 +163,6 @@ function getOperatingSystemDisplayName(os) {
     } catch (e) {
         log.error(e);
     }
-})();
+}
+
+await main();
diff --git a/ext/js/pages/permissions-main.js b/ext/js/pages/permissions-main.js
index 58dae310..e4ac3f3d 100644
--- a/ext/js/pages/permissions-main.js
+++ b/ext/js/pages/permissions-main.js
@@ -86,7 +86,8 @@ function setupPermissionsToggles() {
     }
 }
 
-(async () => {
+/** Entry point. */
+async function main() {
     try {
         const documentFocusController = new DocumentFocusController();
         documentFocusController.prepare();
@@ -140,4 +141,6 @@ function setupPermissionsToggles() {
     } catch (e) {
         log.error(e);
     }
-})();
+}
+
+await main();
diff --git a/ext/js/pages/settings/popup-preview-frame-main.js b/ext/js/pages/settings/popup-preview-frame-main.js
index bce485fe..7b42e11a 100644
--- a/ext/js/pages/settings/popup-preview-frame-main.js
+++ b/ext/js/pages/settings/popup-preview-frame-main.js
@@ -22,7 +22,8 @@ import {HotkeyHandler} from '../../input/hotkey-handler.js';
 import {yomitan} from '../../yomitan.js';
 import {PopupPreviewFrame} from './popup-preview-frame.js';
 
-(async () => {
+/** Entry point. */
+async function main() {
     try {
         await yomitan.prepare();
 
@@ -47,4 +48,6 @@ import {PopupPreviewFrame} from './popup-preview-frame.js';
     } catch (e) {
         log.error(e);
     }
-})();
+}
+
+await main();
diff --git a/ext/js/pages/settings/settings-main.js b/ext/js/pages/settings/settings-main.js
index 3f0dac3f..3abe3bcf 100644
--- a/ext/js/pages/settings/settings-main.js
+++ b/ext/js/pages/settings/settings-main.js
@@ -58,7 +58,8 @@ async function setupGenericSettingsController(genericSettingController) {
     await genericSettingController.refresh();
 }
 
-(async () => {
+/** Entry point. */
+async function main() {
     try {
         const documentFocusController = new DocumentFocusController();
         documentFocusController.prepare();
@@ -174,4 +175,6 @@ async function setupGenericSettingsController(genericSettingController) {
     } catch (e) {
         log.error(e);
     }
-})();
+}
+
+await main();
diff --git a/ext/js/pages/welcome-main.js b/ext/js/pages/welcome-main.js
index d208e996..fbb60fe8 100644
--- a/ext/js/pages/welcome-main.js
+++ b/ext/js/pages/welcome-main.js
@@ -48,7 +48,8 @@ async function setupGenericSettingsController(genericSettingController) {
     await genericSettingController.refresh();
 }
 
-(async () => {
+/** Entry point. */
+async function main() {
     try {
         const documentFocusController = new DocumentFocusController();
         documentFocusController.prepare();
@@ -104,4 +105,6 @@ async function setupGenericSettingsController(genericSettingController) {
     } catch (e) {
         log.error(e);
     }
-})();
+}
+
+await main();
diff --git a/ext/js/templates/sandbox/template-renderer-frame-main.js b/ext/js/templates/sandbox/template-renderer-frame-main.js
index 43b17b1e..f5868aff 100644
--- a/ext/js/templates/sandbox/template-renderer-frame-main.js
+++ b/ext/js/templates/sandbox/template-renderer-frame-main.js
@@ -19,9 +19,12 @@
 import {AnkiTemplateRenderer} from './anki-template-renderer.js';
 import {TemplateRendererFrameApi} from './template-renderer-frame-api.js';
 
-(async () => {
+/** Entry point. */
+async function main() {
     const ankiTemplateRenderer = new AnkiTemplateRenderer();
     await ankiTemplateRenderer.prepare();
     const templateRendererFrameApi = new TemplateRendererFrameApi(ankiTemplateRenderer.templateRenderer);
     templateRendererFrameApi.prepare();
-})();
+}
+
+await main();
diff --git a/jsconfig.json b/jsconfig.json
index 0f780ead..82048af1 100644
--- a/jsconfig.json
+++ b/jsconfig.json
@@ -1,7 +1,7 @@
 {
     "compilerOptions": {
-        "module": "ES2020",
-        "target": "ES2020",
+        "module": "ES2022",
+        "target": "ES2022",
         "checkJs": true,
         "moduleResolution": "node",
         "strict": true,