Duffer Derek

import { IDelay } from "./delay.interface";
import { IBackOffOptions } from "../options";
import { JitterFactory } from "../jitter/jitter.factory";

export abstract class Delay implements IDelay {
  protected attempt = 0;
  constructor(private options: IBackOffOptions) {}

  public apply() {
    return new Promise(resolve => setTimeout(resolve, this.jitteredDelay));
  }

  public setAttemptNumber(attempt: number) {
    this.attempt = attempt;
  }

  private get jitteredDelay() {
    const jitter = JitterFactory(this.options);
    return jitter(this.delay);
  }

  private get delay() {
    const constant = this.options.startingDelay;
    const base = this.options.timeMultiple;
    const power = this.numOfDelayedAttempts;
    const delay = constant * Math.pow(base, power);

    return Math.min(delay, this.options.maxDelay);
  }

  protected get numOfDelayedAttempts() {
    return this.attempt;
  }
}