map-wrappers.ts

class MapWrapper implements Map<string, any> {
	constructor(readonly object: any) {}
	
	clear(): void {
		for (let key of this.keys())
			delete this.object[key];
	}
	delete(key: string): boolean {
		if (!this.has(key))
			return false;
		delete this.object[key];
		return true;
	}
	forEach(callbackfn: (value: any, key: string, map: Map<string, any>) => void, thisArg?: any): void {
		for (let entry of this.entries())
			callbackfn(entry[1], entry[0], this);
	}
	get(key: string) {
		return this.object[key];
	}
	has(key: string): boolean {
		return typeof this.object[key] !== 'undefined';
	}
	set(key: string, value: any): this {
		this.object[key] = value;
		return this;
	}
	get size(): number {
		return Object.keys(this.object).length;
	}
	[Symbol.iterator](): IterableIterator<[string, any]> {
		return this.entries();
	}
	*entries(): IterableIterator<[string, any]> {
		const entries = Object.entries<any>(this.object);
		for (let entry of entries)
			yield entry;
	}
	*keys(): IterableIterator<string> {
		const keys = Object.keys(this.object);
		for (let key of keys)
			yield key;
	}
	*values(): IterableIterator<any> {
		const values = Object.values(this.object);
		for (let value of values)
			yield value;
	}
	[Symbol.toStringTag]: string;
}

const x: any = {};
x.wat = 'george';
const wrapper = new MapWrapper(x);
assert(wrapper.size === 1);
wrapper.set('foo', 42);
assert(x.foo === 42);
for (let entry of wrapper.entries())
	console.log(entry);
process.exit();