Separate core classes into separate files (#545)

5 files changed, 809 insertions, 0 deletions

diff --git a/ext/js/core/dynamic-property.js b/ext/js/core/dynamic-property.js
new file mode 100644
index 00000000..5d8b4716
--- /dev/null
+++ b/ext/js/core/dynamic-property.js
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2023-2024  Yomitan Authors
+ * Copyright (C) 2019-2022  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 {EventDispatcher} from './event-dispatcher.js';
+import {generateId} from './utilities.js';
+
+/**
+ * Class representing a generic value with an override stack.
+ * Changes can be observed by listening to the 'change' event.
+ * @template [T=unknown]
+ * @augments EventDispatcher<import('dynamic-property').Events<T>>
+ */
+export class DynamicProperty extends EventDispatcher {
+    /**
+     * Creates a new instance with the specified value.
+     * @param {T} value The value to assign.
+     */
+    constructor(value) {
+        super();
+        /** @type {T} */
+        this._value = value;
+        /** @type {T} */
+        this._defaultValue = value;
+        /** @type {{value: T, priority: number, token: string}[]} */
+        this._overrides = [];
+    }
+
+    /**
+     * Gets the default value for the property, which is assigned to the
+     * public value property when no overrides are present.
+     * @type {T}
+     */
+    get defaultValue() {
+        return this._defaultValue;
+    }
+
+    /**
+     * Assigns the default value for the property. If no overrides are present
+     * and if the value is different than the current default value,
+     * the 'change' event will be triggered.
+     * @param {T} value The value to assign.
+     */
+    set defaultValue(value) {
+        this._defaultValue = value;
+        if (this._overrides.length === 0) { this._updateValue(); }
+    }
+
+    /**
+     * Gets the current value for the property, taking any overrides into account.
+     * @type {T}
+     */
+    get value() {
+        return this._value;
+    }
+
+    /**
+     * Gets the number of overrides added to the property.
+     * @type {number}
+     */
+    get overrideCount() {
+        return this._overrides.length;
+    }
+
+    /**
+     * Adds an override value with the specified priority to the override stack.
+     * Values with higher priority will take precedence over those with lower.
+     * For tie breaks, the override value added first will take precedence.
+     * If the newly added override has the highest priority of all overrides
+     * and if the override value is different from the current value,
+     * the 'change' event will be fired.
+     * @param {T} value The override value to assign.
+     * @param {number} [priority] The priority value to use, as a number.
+     * @returns {import('core').TokenString} A string token which can be passed to the clearOverride function
+     *   to remove the override.
+     */
+    setOverride(value, priority = 0) {
+        const overridesCount = this._overrides.length;
+        let i = 0;
+        for (; i < overridesCount; ++i) {
+            if (priority > this._overrides[i].priority) { break; }
+        }
+        const token = generateId(16);
+        this._overrides.splice(i, 0, {value, priority, token});
+        if (i === 0) { this._updateValue(); }
+        return token;
+    }
+
+    /**
+     * Removes a specific override value. If the removed override
+     * had the highest priority, and the new value is different from
+     * the previous value, the 'change' event will be fired.
+     * @param {import('core').TokenString} token The token for the corresponding override which is to be removed.
+     * @returns {boolean} `true` if an override was returned, `false` otherwise.
+     */
+    clearOverride(token) {
+        for (let i = 0, ii = this._overrides.length; i < ii; ++i) {
+            if (this._overrides[i].token === token) {
+                this._overrides.splice(i, 1);
+                if (i === 0) { this._updateValue(); }
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Updates the current value using the current overrides and default value.
+     * If the new value differs from the previous value, the 'change' event will be fired.
+     */
+    _updateValue() {
+        const value = this._overrides.length > 0 ? this._overrides[0].value : this._defaultValue;
+        if (this._value === value) { return; }
+        this._value = value;
+        this.trigger('change', {value});
+    }
+}
diff --git a/ext/js/core/event-dispatcher.js b/ext/js/core/event-dispatcher.js
new file mode 100644
index 00000000..75f2fdd3
--- /dev/null
+++ b/ext/js/core/event-dispatcher.js
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2023-2024  Yomitan Authors
+ * Copyright (C) 2019-2022  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/>.
+ */
+
+/**
+ * The following typedef is required because the JSDoc `implements` tag doesn't work with `import()`.
+ * https://github.com/microsoft/TypeScript/issues/49905
+ * @typedef {import('core').EventDispatcherOffGeneric} EventDispatcherOffGeneric
+ */
+
+/**
+ * Base class controls basic event dispatching.
+ * @template {import('core').EventSurface} TSurface
+ * @implements {EventDispatcherOffGeneric}
+ */
+export class EventDispatcher {
+    /**
+     * Creates a new instance.
+     */
+    constructor() {
+        /** @type {Map<import('core').EventNames<TSurface>, import('core').EventHandlerAny[]>} */
+        this._eventMap = new Map();
+    }
+
+    /**
+     * Triggers an event with the given name and specified argument.
+     * @template {import('core').EventNames<TSurface>} TName
+     * @param {TName} eventName The string representing the event's name.
+     * @param {import('core').EventArgument<TSurface, TName>} details The argument passed to the callback functions.
+     * @returns {boolean} `true` if any callbacks were registered, `false` otherwise.
+     */
+    trigger(eventName, details) {
+        const callbacks = this._eventMap.get(eventName);
+        if (typeof callbacks === 'undefined') { return false; }
+
+        for (const callback of callbacks) {
+            callback(details);
+        }
+        return true;
+    }
+
+    /**
+     * Adds a single event listener to a specific event.
+     * @template {import('core').EventNames<TSurface>} TName
+     * @param {TName} eventName The string representing the event's name.
+     * @param {import('core').EventHandler<TSurface, TName>} callback The event listener callback to add.
+     */
+    on(eventName, callback) {
+        let callbacks = this._eventMap.get(eventName);
+        if (typeof callbacks === 'undefined') {
+            callbacks = [];
+            this._eventMap.set(eventName, callbacks);
+        }
+        callbacks.push(callback);
+    }
+
+    /**
+     * Removes a single event listener from a specific event.
+     * @template {import('core').EventNames<TSurface>} TName
+     * @param {TName} eventName The string representing the event's name.
+     * @param {import('core').EventHandler<TSurface, TName>} callback The event listener callback to add.
+     * @returns {boolean} `true` if the callback was removed, `false` otherwise.
+     */
+    off(eventName, callback) {
+        const callbacks = this._eventMap.get(eventName);
+        if (typeof callbacks === 'undefined') { return false; }
+
+        const ii = callbacks.length;
+        for (let i = 0; i < ii; ++i) {
+            if (callbacks[i] === callback) {
+                callbacks.splice(i, 1);
+                if (callbacks.length === 0) {
+                    this._eventMap.delete(eventName);
+                }
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Checks if an event has any listeners.
+     * @template {import('core').EventNames<TSurface>} TName
+     * @param {TName} eventName The string representing the event's name.
+     * @returns {boolean} `true` if the event has listeners, `false` otherwise.
+     */
+    hasListeners(eventName) {
+        const callbacks = this._eventMap.get(eventName);
+        return (typeof callbacks !== 'undefined' && callbacks.length > 0);
+    }
+}
diff --git a/ext/js/core/event-listener-collection.js b/ext/js/core/event-listener-collection.js
new file mode 100644
index 00000000..87d18a90
--- /dev/null
+++ b/ext/js/core/event-listener-collection.js
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2023-2024  Yomitan Authors
+ * Copyright (C) 2019-2022  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/>.
+ */
+
+/**
+ * Class which stores event listeners added to various objects, making it easy to remove them in bulk.
+ */
+export class EventListenerCollection {
+    /**
+     * Creates a new instance.
+     */
+    constructor() {
+        /** @type {import('event-listener-collection').EventListenerDetails[]} */
+        this._eventListeners = [];
+    }
+
+    /**
+     * Returns the number of event listeners that are currently in the object.
+     * @type {number}
+     */
+    get size() {
+        return this._eventListeners.length;
+    }
+
+    /**
+     * Adds an event listener using `object.addEventListener`. The listener will later be removed using `object.removeEventListener`.
+     * @param {import('event-listener-collection').EventTarget} target The object to add the event listener to.
+     * @param {string} type The name of the event.
+     * @param {EventListener | EventListenerObject | import('event-listener-collection').EventListenerFunction} listener The callback listener.
+     * @param {AddEventListenerOptions | boolean} [options] Options for the event.
+     */
+    addEventListener(target, type, listener, options) {
+        target.addEventListener(type, listener, options);
+        this._eventListeners.push({type: 'removeEventListener', target, eventName: type, listener, options});
+    }
+
+    /**
+     * Adds an event listener using `object.addListener`. The listener will later be removed using `object.removeListener`.
+     * @template {import('event-listener-collection').EventListenerFunction} TCallback
+     * @template [TArgs=unknown]
+     * @param {import('event-listener-collection').ExtensionEvent<TCallback, TArgs>} target The object to add the event listener to.
+     * @param {TCallback} callback The callback.
+     * @param {TArgs[]} args The extra argument array passed to the `addListener`/`removeListener` function.
+     */
+    addListener(target, callback, ...args) {
+        target.addListener(callback, ...args);
+        this._eventListeners.push({type: 'removeListener', target, callback, args});
+    }
+
+    /**
+     * Adds an event listener using `object.on`. The listener will later be removed using `object.off`.
+     * @template {import('core').EventSurface} TSurface
+     * @template {import('core').EventNames<TSurface>} TName
+     * @param {import('./event-dispatcher.js').EventDispatcher<TSurface>} target The object to add the event listener to.
+     * @param {TName} eventName The string representing the event's name.
+     * @param {import('core').EventHandler<TSurface, TName>} callback The event listener callback to add.
+     */
+    on(target, eventName, callback) {
+        target.on(eventName, callback);
+        this._eventListeners.push({type: 'off', eventName, target, callback});
+    }
+
+    /**
+     * Removes all event listeners added to objects for this instance and clears the internal list of event listeners.
+     */
+    removeAllEventListeners() {
+        if (this._eventListeners.length === 0) { return; }
+        for (const item of this._eventListeners) {
+            switch (item.type) {
+                case 'removeEventListener':
+                    item.target.removeEventListener(item.eventName, item.listener, item.options);
+                    break;
+                case 'removeListener':
+                    item.target.removeListener(item.callback, ...item.args);
+                    break;
+                case 'off':
+                    item.target.off(item.eventName, item.callback);
+                    break;
+            }
+        }
+        this._eventListeners = [];
+    }
+}
diff --git a/ext/js/core/logger.js b/ext/js/core/logger.js
new file mode 100644
index 00000000..165e1ae2
--- /dev/null
+++ b/ext/js/core/logger.js
@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2023-2024  Yomitan Authors
+ * Copyright (C) 2019-2022  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 {EventDispatcher} from './event-dispatcher.js';
+import {ExtensionError} from './extension-error.js';
+
+/**
+ * This class handles logging of messages to the console and triggering
+ * an event for log calls.
+ * @augments EventDispatcher<import('log').Events>
+ */
+export class Logger extends EventDispatcher {
+    /**
+     * Creates a new instance.
+     */
+    constructor() {
+        super();
+        /** @type {string} */
+        this._extensionName = 'Yomitan';
+        try {
+            const {name, version} = chrome.runtime.getManifest();
+            this._extensionName = `${name} ${version}`;
+        } catch (e) {
+            // NOP
+        }
+    }
+
+    /**
+     * Logs a generic error. This will trigger the 'log' event with the same arguments as the function invocation.
+     * @param {unknown} error The error to log. This is typically an `Error` or `Error`-like object.
+     * @param {import('log').LogLevel} level The level to log at. Values include `'info'`, `'debug'`, `'warn'`, and `'error'`.
+     *   Other values will be logged at a non-error level.
+     * @param {?import('log').LogContext} [context] An optional context object for the error which should typically include a `url` field.
+     */
+    log(error, level, context = null) {
+        if (typeof context !== 'object' || context === null) {
+            context = {url: location.href};
+        }
+
+        let errorString;
+        try {
+            if (typeof error === 'string') {
+                errorString = error;
+            } else {
+                errorString = (
+                    typeof error === 'object' && error !== null ?
+                    error.toString() :
+                    `${error}`
+                );
+                if (/^\[object \w+\]$/.test(errorString)) {
+                    errorString = JSON.stringify(error);
+                }
+            }
+        } catch (e) {
+            errorString = `${error}`;
+        }
+
+        let errorStack;
+        try {
+            errorStack = (
+                error instanceof Error ?
+                (typeof error.stack === 'string' ? error.stack.trimEnd() : '') :
+                ''
+            );
+        } catch (e) {
+            errorStack = '';
+        }
+
+        let errorData;
+        try {
+            if (error instanceof ExtensionError) {
+                errorData = error.data;
+            }
+        } catch (e) {
+            // NOP
+        }
+
+        if (errorStack.startsWith(errorString)) {
+            errorString = errorStack;
+        } else if (errorStack.length > 0) {
+            errorString += `\n${errorStack}`;
+        }
+
+        let message = `${this._extensionName} has encountered a problem.`;
+        message += `\nOriginating URL: ${context.url}\n`;
+        message += errorString;
+        if (typeof errorData !== 'undefined') {
+            message += `\nData: ${JSON.stringify(errorData, null, 4)}`;
+        }
+        message += '\n\nIssues can be reported at https://github.com/themoeway/yomitan/issues';
+
+        /* eslint-disable no-console */
+        switch (level) {
+            case 'log': console.log(message); break;
+            case 'info': console.info(message); break;
+            case 'debug': console.debug(message); break;
+            case 'warn': console.warn(message); break;
+            case 'error': console.error(message); break;
+        }
+        /* eslint-enable no-console */
+
+        this.trigger('log', {error, level, context});
+    }
+
+    /**
+     * Logs a warning. This function invokes `log` internally.
+     * @param {unknown} error The error to log. This is typically an `Error` or `Error`-like object.
+     * @param {?import('log').LogContext} context An optional context object for the error which should typically include a `url` field.
+     */
+    warn(error, context = null) {
+        this.log(error, 'warn', context);
+    }
+
+    /**
+     * Logs an error. This function invokes `log` internally.
+     * @param {unknown} error The error to log. This is typically an `Error` or `Error`-like object.
+     * @param {?import('log').LogContext} context An optional context object for the error which should typically include a `url` field.
+     */
+    error(error, context = null) {
+        this.log(error, 'error', context);
+    }
+
+    /**
+     * @param {import('log').LogLevel} errorLevel
+     * @returns {import('log').LogErrorLevelValue}
+     */
+    getLogErrorLevelValue(errorLevel) {
+        switch (errorLevel) {
+            case 'log':
+            case 'info':
+            case 'debug':
+                return 0;
+            case 'warn': return 1;
+            case 'error': return 2;
+        }
+    }
+}
+
+/**
+ * This object is the default logger used by the runtime.
+ */
+export const log = new Logger();
diff --git a/ext/js/core/utilities.js b/ext/js/core/utilities.js
new file mode 100644
index 00000000..1fc2da42
--- /dev/null
+++ b/ext/js/core/utilities.js
@@ -0,0 +1,319 @@
+/*
+ * Copyright (C) 2023-2024  Yomitan Authors
+ * Copyright (C) 2019-2022  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/>.
+ */
+
+/**
+ * Checks whether a given value is a non-array object.
+ * @param {unknown} value The value to check.
+ * @returns {boolean} `true` if the value is an object and not an array, `false` otherwise.
+ */
+export function isObject(value) {
+    return typeof value === 'object' && value !== null && !Array.isArray(value);
+}
+
+/**
+ * Converts any string into a form that can be passed into the RegExp constructor.
+ * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions
+ * @param {string} string The string to convert to a valid regular expression.
+ * @returns {string} The escaped string.
+ */
+export function escapeRegExp(string) {
+    return string.replace(/[.*+\-?^${}()|[\]\\]/g, '\\$&');
+}
+
+/**
+ * Reverses a string.
+ * @param {string} string The string to reverse.
+ * @returns {string} The returned string, which retains proper UTF-16 surrogate pair order.
+ */
+export function stringReverse(string) {
+    return [...string].reverse().join('');
+}
+
+/**
+ * Creates a deep clone of an object or value. This is similar to `parseJson(JSON.stringify(value))`.
+ * @template [T=unknown]
+ * @param {T} value The value to clone.
+ * @returns {T} A new clone of the value.
+ * @throws An error if the value is circular and cannot be cloned.
+ */
+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} */ (
+                    Array.isArray(value) ?
+                    cloneArray(value, visited) :
+                    cloneObject(/** @type {import('core').SerializableObject} */ (value), visited)
+            );
+        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 {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);
+    }
+}
+
+/**
+ * Checks if an object or value is deeply equal to another object or value.
+ * @param {unknown} value1 The first value to check.
+ * @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 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 (
+                    array ?
+                    areArraysEqual(/** @type {unknown[]} */ (value1), /** @type {unknown[]} */ (value2), visited1) :
+                    areObjectsEqual(/** @type {import('core').UnknownObject} */ (value1), /** @type {import('core').UnknownObject} */ (value2), visited1)
+            );
+        }
+        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; }
+    }
+
+    return true;
+}
+
+/**
+ * @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; }
+
+    for (let i = 0; i < length; ++i) {
+        if (!deepEqualInternal(value1[i], value2[i], visited1)) { return false; }
+    }
+
+    return true;
+}
+
+/**
+ * Creates a new base-16 (lower case) string of a sequence of random bytes of the given length.
+ * @param {number} length The number of bytes the string represents. The returned string's length will be twice as long.
+ * @returns {string} A string of random characters.
+ */
+export function generateId(length) {
+    const array = new Uint8Array(length);
+    crypto.getRandomValues(array);
+    let id = '';
+    for (const value of array) {
+        id += value.toString(16).padStart(2, '0');
+    }
+    return id;
+}
+
+/**
+ * Creates an unresolved promise that can be resolved later, outside the promise's executor function.
+ * @template [T=unknown]
+ * @returns {import('core').DeferredPromiseDetails<T>} An object `{promise, resolve, reject}`, containing the promise and the resolve/reject functions.
+ */
+export function deferPromise() {
+    /** @type {((value: T) => void)|undefined} */
+    let resolve;
+    /** @type {((reason?: import('core').RejectionReason) => void)|undefined} */
+    let reject;
+    const promise = new Promise((resolve2, reject2) => {
+        resolve = resolve2;
+        reject = reject2;
+    });
+    return {
+        promise,
+        resolve: /** @type {(value: T) => void} */ (resolve),
+        reject: /** @type {(reason?: import('core').RejectionReason) => void} */ (reject)
+    };
+}
+
+/**
+ * Creates a promise that is resolved after a set delay.
+ * @param {number} delay How many milliseconds until the promise should be resolved. If 0, the promise is immediately resolved.
+ * @returns {Promise<void>} A promise with two additional properties: `resolve` and `reject`, which can be used to complete the promise early.
+ */
+export function promiseTimeout(delay) {
+    return delay <= 0 ? Promise.resolve() : new Promise((resolve) => { setTimeout(resolve, delay); });
+}
+
+/**
+ * Creates a promise that will resolve after the next animation frame, using `requestAnimationFrame`.
+ * @param {number} [timeout] A maximum duration (in milliseconds) to wait until the promise resolves. If null or omitted, no timeout is used.
+ * @returns {Promise<{time: number, timeout: boolean}>} A promise that is resolved with `{time, timeout}`, where `time` is the timestamp from `requestAnimationFrame`,
+ *   and `timeout` is a boolean indicating whether the cause was a timeout or not.
+ * @throws The promise throws an error if animation is not supported in this context, such as in a service worker.
+ */
+export function promiseAnimationFrame(timeout) {
+    return new Promise((resolve, reject) => {
+        if (typeof cancelAnimationFrame !== 'function' || typeof requestAnimationFrame !== 'function') {
+            reject(new Error('Animation not supported in this context'));
+            return;
+        }
+
+        /** @type {?import('core').Timeout} */
+        let timer = null;
+        /** @type {?number} */
+        let frameRequest = null;
+        /**
+         * @param {number} time
+         */
+        const onFrame = (time) => {
+            frameRequest = null;
+            if (timer !== null) {
+                clearTimeout(timer);
+                timer = null;
+            }
+            resolve({time, timeout: false});
+        };
+        const onTimeout = () => {
+            timer = null;
+            if (frameRequest !== null) {
+                // eslint-disable-next-line no-undef
+                cancelAnimationFrame(frameRequest);
+                frameRequest = null;
+            }
+            resolve({time: performance.now(), timeout: true});
+        };
+
+        // eslint-disable-next-line no-undef
+        frameRequest = requestAnimationFrame(onFrame);
+        if (typeof timeout === 'number') {
+            timer = setTimeout(onTimeout, timeout);
+        }
+    });
+}