Delay the execution of asynchronous functions.

Debouncer.ts

export class Debouncer {

  public promiseGenerator: () => Promise;
  public delayInMilliseconds: number;

  private timeoutCompleted: bool;
  private timeoutCached: () => void;

  constructor (generator: () => Promise, delayInMilliseconds: number) {
    this.promiseGenerator = generator;
    this.delayInMilliseconds = delayInMilliseconds;
    this.timeoutCompleted = false;
  }

  public async attempt () {
    if (this.timeoutCompleted)
      return this.promiseGenerator(args);

    this.timeoutCached = new setTimeout(
      () => this.timeoutCompleted = true, 
      this.delayInMilliseconds)
  }

}