ken107

export function createWavHeader(dataLength: number, sampleRate: number, bitDepth: number, channels: number) {
  const headerLength = 44; // Standard size of WAV header
  const totalLength = headerLength + dataLength;

  const buffer = new ArrayBuffer(headerLength);
  const view = new DataView(buffer);

  // RIFF chunk descriptor
  writeString(view, 0, 'RIFF'); // ChunkID
  view.setUint32(4, totalLength - 8, true); // ChunkSize (file size - 8 bytes)

ken107

function makeAudioPlayer(audio) {
  audio.oncanplay = () => sm.trigger("onCanPlay")
  audio.onerror = () => sm.trigger("onError", new Error(audio.error.message || audio.error.code))
  audio.onended = () => sm.trigger("onEnd")

  const sm = new StateMachine({
    IDLE: {
      load(url) {
        audio.src = url
        return "LOADING_PAUSED"

ken107

export function makeValidGetter<T extends {isValid(): boolean}>(generator: () => Promise<T>): () => Promise<T> {
  let value: T|undefined
  let promise: Promise<T>|undefined
  return async function() {
    if (value?.isValid()) return value
    if (promise) return await promise
    promise = generator()
      .then(result => {
        value = result
        promise = undefined

ken107

function simulate(element, eventName, options) {
    var opt = {
        pointerX: 0,
        pointerY: 0,
        button: 0,
        ctrlKey: false,
        altKey: false,
        shiftKey: false,
        metaKey: false,
        bubbles: true,

ken107

/**
 * Repeat an action
 * @param {Object} opt - options
 * @param {Function} opt.action - action to repeat
 * @param {Function} opt.until - termination condition
 * @param {Number} opt.delay - delay between actions
 * @param {Number} opt.max - maximum number of repetitions
 * @returns {Promise}
 */
function repeat(opt) {

ken107

function setIdleTimeout(millis, onIdle, onUnidle) {
    var timeout = 0;
    startTimer();

    function startTimer() {
        timeout = setTimeout(onExpires, millis);
        document.addEventListener("mousemove", onActivity);
        document.addEventListener("keydown", onActivity);
        document.addEventListener("touchstart", onActivity);
    }