Function Tween

esm/gsap-core.js:3152–3309

(targets, vars, position, skipInherit)

  _inheritsLoose(Tween, _Animation2);

  function Tween(targets, vars, position, skipInherit) {
    var _this3;

    if (typeof vars === "number") {
      position.duration = vars;
      vars = position;
      position = null;
    }

    _this3 = _Animation2.call(this, skipInherit ? vars : _inheritDefaults(vars)) || this;
    var _this3$vars = _this3.vars,
        duration = _this3$vars.duration,
        delay = _this3$vars.delay,
        immediateRender = _this3$vars.immediateRender,
        stagger = _this3$vars.stagger,
        overwrite = _this3$vars.overwrite,
        keyframes = _this3$vars.keyframes,
        defaults = _this3$vars.defaults,
        scrollTrigger = _this3$vars.scrollTrigger,
        parent = vars.parent || _globalTimeline,
        parsedTargets = (_isArray(targets) || _isTypedArray(targets) ? _isNumber(targets[0]) : "length" in vars) ? [targets] : toArray(targets),
        tl,
        i,
        copy,
        l,
        p,
        curTarget,
        staggerFunc,
        staggerVarsToMerge;
    _this3._targets = parsedTargets.length ? _harness(parsedTargets) : _warn("GSAP target " + targets + " not found. https://gsap.com", !_config.nullTargetWarn) || [];
    _this3._ptLookup = []; //PropTween lookup. An array containing an object for each target, having keys for each tweening property

    _this3._overwrite = overwrite;

    if (keyframes || stagger || _isFuncOrString(duration) || _isFuncOrString(delay)) {
      vars = _this3.vars;
      var easeReverse = vars.easeReverse || vars.yoyoEase;
      tl = _this3.timeline = new Timeline({
        data: "nested",
        defaults: defaults || {},
        targets: parent && parent.data === "nested" ? parent.vars.targets : parsedTargets
      }); // we need to store the targets because for staggers and keyframes, we end up creating an individual tween for each but function-based values need to know the index and the whole Array of targets.

      tl.kill();
      tl.parent = tl._dp = _assertThisInitialized(_this3);
      tl._start = 0;

      if (stagger || _isFuncOrString(duration) || _isFuncOrString(delay)) {
        l = parsedTargets.length;
        staggerFunc = stagger && distribute(stagger);

        if (_isObject(stagger)) {
          //users can pass in callbacks like onStart/onComplete in the stagger object. These should fire with each individual tween.
          for (p in stagger) {
            if (~_staggerTweenProps.indexOf(p)) {
              staggerVarsToMerge || (staggerVarsToMerge = {});
              staggerVarsToMerge[p] = stagger[p];
            }