Debounce function

debounce.js

/**
 * Debounce function
 * based on https://davidwalsh.name/essential-javascript-functions
 */
 
function debounce(func, wait, immediate) {
  var timeout;
  return function () {
    var context = this,
      args = arguments,
      later,
      callNow;

    later = function () {
      timeout = null;
      if (!immediate) {
        func.apply(context, args);
      }
    };
    callNow = immediate && !timeout;
    clearTimeout(timeout);
    timeout = setTimeout(later, wait);
    if (callNow) {
      func.apply(context, args);
    }
  };
}

// Use it like this ...

var debouncedUpdate;
debouncedUpdate = debounce(function (value) {
  myHandleChangeFunction(value);
}, 50);

$myInputFormField.on('input change keyup', function () {
  debouncedUpdate(this.value);
});

debounce_v2.js

/**
 * Debounce function v2
 * based on https://davidwalsh.name/essential-javascript-functions
 * with leading/trailing support as seen on https://lodash.com/docs/4.17.10#debounce
 */
 
function debounce(func, wait, options) {
  var timeout;
  var debounceCount = 0;
  options = options || {};
  options.leading = options.leading || false;
  options.trailing = options.trailing || true;

  return function () {
    var context = this,
      args = arguments,
      later,
      callNow;

    debounceCount += 1;

    later = function () {
      timeout = null;
      // If leadEqualsTrail === 1 the debounce function was only triggered once
      var leadEqualsTrail = debounceCount === 1;
      if ((options.leading && !leadEqualsTrail) && options.trailing) {
        func.apply(context, args);
      }
      debounceCount = 0;
    };
    callNow = options.leading && !timeout;
    clearTimeout(timeout);
    timeout = setTimeout(later, wait);
    if (callNow) {
      func.apply(context, args);
    }
  };
}

// Use it like this ...

var debouncedUpdate;
debouncedUpdate = debounce(function (value) {
  myHandleChangeFunction(value);
}, 500, { leading: true, trailing: true });

$myInputFormField.on('input change keyup', function () {
  debouncedUpdate(this.value);
});