@v4fire/client/src/core/component/engines/helpers.ts

V4Fire client core library

/*!
 * V4Fire Client Core
 * https://github.com/V4Fire/Client
 *
 * Released under the MIT license
 * https://github.com/V4Fire/Client/blob/master/LICENSE
 */

import { fakeCopyLabel } from 'core/component/watch';

const
	toNonFakeObject = Symbol('Link to a non fake object');

/**
 * Returns a "fake" copy of the specified (weak)map/(weak)set object
 * @param obj
 */
export function fakeMapSetCopy<
	T extends Map<unknown, unknown> | WeakMap<object, unknown> | Set<unknown> | WeakSet<object>
>(obj: T): T {
	obj = obj[toNonFakeObject] ?? obj;

	const
		Constructor = obj.constructor,
		proto = Constructor.prototype;

	// @ts-ignore (constructor)
	const wrap = new Constructor();

	for (let keys = Object.getOwnPropertyNames(proto), i = 0; i < keys.length; i++) {
		const
			key = keys[i],
			desc = Object.getOwnPropertyDescriptor(proto, key);

		if (!desc) {
			continue;
		}

		if (Object.isFunction(desc.value)) {
			Object.defineProperty(wrap, key, {
				...desc,
				value: obj[key].bind(obj)
			});

		// eslint-disable-next-line @typescript-eslint/unbound-method
		} else if (Object.isFunction(desc.get)) {
			Object.defineProperty(wrap, key, {
				...desc,
				get: () => obj[key],
				set: desc.set && ((v) => obj[key] = v)
			});
		}
	}

	wrap[Symbol.iterator] = obj[Symbol.iterator]?.bind(obj);
	wrap[Symbol.asyncIterator] = obj[Symbol.asyncIterator]?.bind(obj);

	wrap[toNonFakeObject] = obj;
	wrap[fakeCopyLabel] = true;

	return wrap;
}