// lets you wait until it is uncorked by someone before running
export default class DedupAwaiter<T> {
	private promise: Promise<T> | null;

	constructor(
		private func: () => Promise<T>
	) {}

	public async callOrDedup(): Promise<T> {
		if (!this.promise) {
			this.promise = new Promise<T>(async (resolve) => {
				resolve(await this.func());
			});
		}
		let promise = this.promise;
		let result = await promise;
		if (promise === this.promise) {
			this.promise = null;
		}
		return result;
	}
}