webpack/lib/util/SortableSet.js

Packs ECMAScript/CommonJs/AMD modules for the browser. Allows you to split your codebase into multiple bundles, which can be loaded on demand. Supports loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/

"use strict";

const NONE = Symbol("not sorted");

/**
 * A subset of Set that offers sorting functionality
 * @template T item type in set
 * @extends {Set<T>}
 */
class SortableSet extends Set {
	/**
	 * Create a new sortable set
	 * @template T
	 * @typedef {(a: T, b: T) => number} SortFunction
	 * @param {Iterable<T>=} initialIterable The initial iterable value
	 * @param {SortFunction<T>=} defaultSort Default sorting function
	 */
	constructor(initialIterable, defaultSort) {
		super(initialIterable);
		/**
		 * @private
		 * @type {undefined | SortFunction<T>}
		 */
		this._sortFn = defaultSort;
		/**
		 * @private
		 * @type {typeof NONE | undefined | ((a: T, b: T) => number)}}
		 */
		this._lastActiveSortFn = NONE;
		/**
		 * @private
		 * @template R
		 * @type {Map<(set: SortableSet<T>) => EXPECTED_ANY, EXPECTED_ANY> | undefined}
		 */
		this._cache = undefined;
		/**
		 * @private
		 * @template R
		 * @type {Map<(set: SortableSet<T>) => EXPECTED_ANY, EXPECTED_ANY> | undefined}
		 */
		this._cacheOrderIndependent = undefined;
	}

	/**
	 * Returns itself.
	 * @param {T} value value to add to set
	 * @returns {this} returns itself
	 */
	add(value) {
		this._lastActiveSortFn = NONE;
		this._invalidateCache();
		this._invalidateOrderedCache();
		super.add(value);
		return this;
	}

	/**
	 * Returns true if value existed in set, false otherwise.
	 * @param {T} value value to delete
	 * @returns {boolean} true if value existed in set, false otherwise
	 */
	delete(value) {
		this._invalidateCache();
		this._invalidateOrderedCache();
		return super.delete(value);
	}

	/**
	 * Describes how this clear operation behaves.
	 * @returns {void}
	 */
	clear() {
		this._invalidateCache();
		this._invalidateOrderedCache();
		return super.clear();
	}

	/**
	 * Sort with a comparer function
	 * @param {SortFunction<T> | undefined} sortFn Sorting comparer function
	 * @returns {void}
	 */
	sortWith(sortFn) {
		if (this.size <= 1 || sortFn === this._lastActiveSortFn) {
			// already sorted - nothing to do
			return;
		}

		/** @type {T[]} */
		const sortedArray = [...this].sort(sortFn);
		super.clear();
		for (let i = 0; i < sortedArray.length; i += 1) {
			super.add(sortedArray[i]);
		}
		this._lastActiveSortFn = sortFn;
		this._invalidateCache();
	}

	sort() {
		this.sortWith(this._sortFn);
		return this;
	}

	/**
	 * Get data from cache
	 * @template {EXPECTED_ANY} R
	 * @param {(set: SortableSet<T>) => R} fn function to calculate value
	 * @returns {R} returns result of fn(this), cached until set changes
	 */
	getFromCache(fn) {
		if (this._cache === undefined) {
			this._cache = new Map();
		} else {
			const result = this._cache.get(fn);
			const data = /** @type {R} */ (result);
			if (data !== undefined) {
				return data;
			}
		}
		const newData = fn(this);
		this._cache.set(fn, newData);
		return newData;
	}

	/**
	 * Get data from cache (ignoring sorting)
	 * @template R
	 * @param {(set: SortableSet<T>) => R} fn function to calculate value
	 * @returns {R} returns result of fn(this), cached until set changes
	 */
	getFromUnorderedCache(fn) {
		if (this._cacheOrderIndependent === undefined) {
			this._cacheOrderIndependent = new Map();
		} else {
			const result = this._cacheOrderIndependent.get(fn);
			const data = /** @type {R} */ (result);
			if (data !== undefined) {
				return data;
			}
		}
		const newData = fn(this);
		this._cacheOrderIndependent.set(fn, newData);
		return newData;
	}

	/**
	 * Invalidates the cached state associated with this value.
	 * @private
	 * @returns {void}
	 */
	_invalidateCache() {
		if (this._cache !== undefined) {
			this._cache.clear();
		}
	}

	/**
	 * Invalidate ordered cache.
	 * @private
	 * @returns {void}
	 */
	_invalidateOrderedCache() {
		if (this._cacheOrderIndependent !== undefined) {
			this._cacheOrderIndependent.clear();
		}
	}

	/**
	 * Returns the raw array.
	 * @returns {T[]} the raw array
	 */
	toJSON() {
		return [...this];
	}
}

module.exports = SortableSet;