Function start

test/angular/1.6/angular-animate.js:1347–1521

()

      }

      function start() {
        if (animationClosed) return;
        if (!node.parentNode) {
          close();
          return;
        }

        // even though we only pause keyframe animations here the pause flag
        // will still happen when transitions are used. Only the transition will
        // not be paused since that is not possible. If the animation ends when
        // paused then it will not complete until unpaused or cancelled.
        var playPause = function(playAnimation) {
          if (!animationCompleted) {
            animationPaused = !playAnimation;
            if (timings.animationDuration) {
              var value = blockKeyframeAnimations(node, animationPaused);
              if (animationPaused) {
                temporaryStyles.push(value);
              } else {
                removeFromArray(temporaryStyles, value);
              }
            }
          } else if (animationPaused && playAnimation) {
            animationPaused = false;
            close();
          }
        };

        // checking the stagger duration prevents an accidentally cascade of the CSS delay style
        // being inherited from the parent. If the transition duration is zero then we can safely
        // rely that the delay value is an intentional stagger delay style.
        var maxStagger = itemIndex > 0
                         && ((timings.transitionDuration && stagger.transitionDuration === 0) ||
                            (timings.animationDuration && stagger.animationDuration === 0))
                         && Math.max(stagger.animationDelay, stagger.transitionDelay);
        if (maxStagger) {
          $timeout(triggerAnimationStart,
                   Math.floor(maxStagger * itemIndex * ONE_SECOND),
                   false);
        } else {
          triggerAnimationStart();
        }

        // this will decorate the existing promise runner with pause/resume methods
        runnerHost.resume = function() {
          playPause(true);
        };

        runnerHost.pause = function() {
          playPause(false);
        };

        function triggerAnimationStart() {
          // just incase a stagger animation kicks in when the animation
          // itself was cancelled entirely
          if (animationClosed) return;

          applyBlocking(false);