mhdSid

public fadeInAudioElementVolume (start: number, end: number, duration: number, callback?: Function): void {
  const delta: number = end - start;
  let startTime: number = null;
  let t: number;
  let factor: number;
  let frame: any;
  const tweenLoop: FrameRequestCallback = (time?: number) => {
      if (!time) {
          time = new Date().getTime();
      }

mhdSid

public iterateBackwards (arrayLength: number, index: number): number {
    return index = (index <= 0) ? arrayLength - 1 : --index, index;
}

public iterateForwards (arrayLength: number, index: number): number {
    return index = (index >= arrayLength - 1) ? 0 : ++index, index;
}

/*
 * Usage