webpack/lib/util/TupleSet.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support 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";

/**
 * @template {any[]} T
 */
class TupleSet {
	constructor(init) {
		this._map = new Map();
		this.size = 0;
		if (init) {
			for (const tuple of init) {
				this.add(...tuple);
			}
		}
	}

	/**
	 * @param  {T} args tuple
	 * @returns {void}
	 */
	add(...args) {
		let map = this._map;
		for (let i = 0; i < args.length - 2; i++) {
			const arg = args[i];
			const innerMap = map.get(arg);
			if (innerMap === undefined) {
				map.set(arg, (map = new Map()));
			} else {
				map = innerMap;
			}
		}

		const beforeLast = args[args.length - 2];
		let set = map.get(beforeLast);
		if (set === undefined) {
			map.set(beforeLast, (set = new Set()));
		}

		const last = args[args.length - 1];
		this.size -= set.size;
		set.add(last);
		this.size += set.size;
	}

	/**
	 * @param  {T} args tuple
	 * @returns {boolean} true, if the tuple is in the Set
	 */
	has(...args) {
		let map = this._map;
		for (let i = 0; i < args.length - 2; i++) {
			const arg = args[i];
			map = map.get(arg);
			if (map === undefined) {
				return false;
			}
		}

		const beforeLast = args[args.length - 2];
		let set = map.get(beforeLast);
		if (set === undefined) {
			return false;
		}

		const last = args[args.length - 1];
		return set.has(last);
	}

	/**
	 * @param {T} args tuple
	 * @returns {void}
	 */
	delete(...args) {
		let map = this._map;
		for (let i = 0; i < args.length - 2; i++) {
			const arg = args[i];
			map = map.get(arg);
			if (map === undefined) {
				return;
			}
		}

		const beforeLast = args[args.length - 2];
		let set = map.get(beforeLast);
		if (set === undefined) {
			return;
		}

		const last = args[args.length - 1];
		this.size -= set.size;
		set.delete(last);
		this.size += set.size;
	}

	/**
	 * @returns {Iterator<T>} iterator
	 */
	[Symbol.iterator]() {
		const iteratorStack = [];
		const tuple = [];
		let currentSetIterator = undefined;

		const next = it => {
			const result = it.next();
			if (result.done) {
				if (iteratorStack.length === 0) return false;
				tuple.pop();
				return next(iteratorStack.pop());
			}
			const [key, value] = result.value;
			iteratorStack.push(it);
			tuple.push(key);
			if (value instanceof Set) {
				currentSetIterator = value[Symbol.iterator]();
				return true;
			} else {
				return next(value[Symbol.iterator]());
			}
		};

		next(this._map[Symbol.iterator]());

		return {
			next() {
				while (currentSetIterator) {
					const result = currentSetIterator.next();
					if (result.done) {
						tuple.pop();
						if (!next(iteratorStack.pop())) {
							currentSetIterator = undefined;
						}
					} else {
						return {
							done: false,
							value: /** @type {T} */ (tuple.concat(result.value))
						};
					}
				}
				return { done: true, value: undefined };
			}
		};
	}
}

module.exports = TupleSet;