Vanilla JS SVG line animation helper, works in IE

svg-animate.js

/**
   * Initialize animation on an SVG path or set of paths, this returns a controller
   * object
   *
   *   var lines = animate({
   *     parent: "#someElement",
   *     selector: ".theActualLines",
   *     duration: 2500
   *   })
   *
   * Then kick off the animation by calling play() on the controller:
   *
   *   lines.play()
   *
   * animate accepts the following options:
   *
   * @param {String} paths A selector describing a set of SVG path elements
   * @param {Number} duration Duration of the animation in milliseconds
   * @param {Object} args - An object containing the following
   * @param {String} args.selector - A selector string describing a set of SVG path elements
   * @param {Number} [args.duration=1500] - Duration of the animation in milliseconds
   * @param {Boolean|String} [args.loop=false] - Loop the animation or not
   * @return {Object}
   */
  var animate = function(args) {
    var duration =
        args.duration !== undefined ? parseInt(args.duration, 10) : 1500,
      parent = args.parent !== undefined ? args.parent : "body",
      pathNodes = $(parent).find(args.selector),
      easing = 1.8;
    /**
     * QuerySelectorAll returns a nodeList, which doesn't support forEach/map/filter/reduce iteration
     */
    for (var n = 0; n < pathNodes.length; n++) {
      var len = pathNodes[n].getTotalLength();
      pathNodes[n].style.strokeDasharray = len - 1 + " " + len;
      pathNodes[n].style.strokeDashoffset = len;
      pathNodes[n].setAttribute("data-length", len);
    }

    var getEndTime = function() {
      return new Date().getTime() + duration;
    };

    var controller = {
      endTime: false
    };

    controller.play = function() {
      var ratio, offset;

      if (controller.endTime === false) {
        controller.endTime = getEndTime();
      }

      ratio = Math.max(0, controller.endTime - new Date().getTime()) / duration;

      for (var n = 0; n < pathNodes.length; n++) {
        var len = pathNodes[n].getAttribute("data-length");
        offset = len * Math.pow(ratio, easing);
        pathNodes[n].style.strokeDashoffset = offset;
      }

      if (args.loop && ratio <= 0) {
        ratio = 1;
        controller.endTime = getEndTime();
      }

      if (ratio > 0) {
        window.requestAnimationFrame(controller.play);
      }
    };
    return controller;
  };