Method map

packages/collection/src/collection.ts:510–518

(fn: (value: Value, key: Key, collection: this) => NewValue, thisArg?: unknown)

		thisArg: This,
	): NewValue[];
	public map<NewValue>(fn: (value: Value, key: Key, collection: this) => NewValue, thisArg?: unknown): NewValue[] {
		if (typeof fn !== 'function') throw new TypeError(`${fn} is not a function`);
		if (thisArg !== undefined) fn = fn.bind(thisArg);
		const iter = this.entries();
		return Array.from({ length: this.size }, (): NewValue => {
			const [key, value] = iter.next().value!;
			return fn(value, key, this);
		});
	}

	/**
	 * Maps each item to another value into a collection. Identical in behavior to