始终触发且仅触发一次的 "transitionend" 事件

Question

我需要一个类似 transitionend 的特殊事件，它在所有转换完成后触发一次，或者如果 CSS.

中没有定义转换则立即触发

这是我到目前为止所想出的：

(function($){

  $.event.special.transitionsComplete = {

    setup: function(data, namespaces, eventHandle){    
      var queue = [],
          style = window.getComputedStyle(this, null),
          computedProps = style.getPropertyValue('transition-property').split(', '),
          computedDurations = style.getPropertyValue('transition-duration').split(', '),
          $node = $(this);          

      // only count properties with duration higher than 0s
      for(var i = 0; i < computedDurations.length; i++)
        if(computedDurations[i] !== '0s')
          queue.push(computedProps[i]);           

      // there are transitions
      if(queue.length > 0){
        $node.on('webkitTransitionEnd.x transitionend.x', function(e){          
          queue.splice(queue.indexOf(e.originalEvent.propertyName));          
          if(queue.length < 1)
            $node.trigger('transitionsComplete');
        });

      // no transitions, fire (almost) immediately
      }else{
        setTimeout(function(){
          $node.trigger('transitionsComplete');
        }, 5);

      }

    },

    teardown: function(namespaces){
      $(this).off('.x');
    }

  };
})(jQuery);

我做了一个活生生的例子here。

唯一的问题是它仅在元素本身具有过渡属性时才有效，忽略来自 children 元素的过渡。如果我将 transitionsComplete 切换到 transitionend，parent 和 child 事件处理程序在 child 转换完成后都是运行。有没有什么方法，或者更好的方法来确定一个元素是否发生了转换或者它的 children？如果可能，我想避免手动检查 children 并检查它们的转换属性。（无论如何这都不可靠，因为即使一些 children 有转换，也不意味着他们会在那个时候活跃）

Answer 1

所以给你，确实我检查了children：http://jsfiddle.net/cegejk59/2/

(function($){

  $.event.special.transitionsComplete = {

    setup: function( data, namespaces, eventHandle ) {

        var allTransitions          = [];
            w                       = window,
            TRANSITION_PROPERTY_KEY = 'transition-property',
            TRANSITION_DURATION_KEY = 'transition-duration',
            $node                   = $( this );

        function collectTransitionsRecursively( node ) {

            var style                   = w.getComputedStyle( node ),
                nodeComputedProperties  = style.getPropertyValue( TRANSITION_PROPERTY_KEY ).split( ', ' ),
                nodeComputedDurations   = style.getPropertyValue( TRANSITION_DURATION_KEY ).split( ', ' );

            for( var i = 0; i < nodeComputedDurations.length; i++ )
                if( nodeComputedDurations[ i ] !== '0s' )
                    allTransitions.push( nodeComputedProperties[ i ] );

            for( var childIndex = 0; childIndex < node.children.length; childIndex++ )
                collectTransitionsRecursively( node.children[ childIndex ] );
        }

        function triggerTransitionsComplete( $onNode ) {

            console.log( "No transitions (left)." );

            $onNode.trigger('transitionsComplete');
        }

        function onNoTransitionsFound() {

            setTimeout( function() {

                triggerTransitionsComplete( $node );
            });
        }

        collectTransitionsRecursively( this );

        if( allTransitions.length == 0 )
            return onNoTransitionsFound();
        else
            console.log( 'remaining', allTransitions );    

        $node.on('webkitTransitionEnd.x transitionend.x', function( e ){ 

            allTransitions.splice(allTransitions.indexOf(e.originalEvent.propertyName));

            if( allTransitions.length == 0 )
                triggerTransitionsComplete( $node );
            else
                console.log('remaining', allTransitions);
        });
    },

    teardown: function( namespaces ) {

      $( this ).off( '.x' );
    }
  };
})(jQuery);


var div = $('div'), p = $('p'), start = new Date().getTime();
console.log('-- start --');
div.addClass('visible');

div.one('transitionsComplete', function(e){
    console.log('complete-div', (new Date().getTime() - start) / 1000);
});

//p.one('transitionsComplete', function(e){
//    console.log('complete-p', (new Date().getTime() - start) / 1000);
//});

Answer 2

我用过 treeWalker api to traverse the original node (root), and all child nodes (elements only), filter out elements without transitions, and collect transitions properties to queue (fiddle)。如您所见，我已经解决了 complete-div 和 complete-p 之间的时差问题，现在它们同时触发（几乎 - 几毫秒）。

有两个警告，对此我没有解决方法：

如果存在由不同方式触发的转换，对于示例一是通过将 .visible 添加到 div 来触发的，并且其他通过添加.invisible，它们将全部添加到queue。该事件永远不会触发，因为 queue 永远不会为空 - 我不知道如何解决这个问题。
如果有快捷方式属性的转换（padding 例如），可能会触发多个 transitionend 事件，例如 transition-property，例如 padding-top、padding-right 等... 将导致数组很快清空 splice(-1, 1) 从数组末尾删除项目。我有一个 workaround，但是这可能会导致问题，因为它可能会删除 queue。最好的解决方法是不要在快捷方式上转换属性。

treeWalker 的代码基于 Ban Nadel 的 - Finding HTML Comment Nodes In The DOM Using TreeWalker。

最后是代码：

(function ($) {

    $.event.special.transitionsComplete = {

        setup: function (data, namespaces, eventHandle) {
            var TRANSITION_PROPERTY = 'transition-property';
            var TRANSITION_DURATION = 'transition-duration';

            var root = this;
            var queue = [];
            var $node = $(this);

            function filter(node) { // filter for treeWalker
                /*** filters transitions which are a string with one '0s'. If more then '0s' is defined it will be catched when creating the queue ***/
                var computedDuration = window.getComputedStyle(node, null)
                    .getPropertyValue(TRANSITION_DURATION);

                return computedDuration === '0s' ? NodeFilter.FILTER_SKIP : NodeFilter.FILTER_ACCEPT;
            }

            filter.acceptNode = filter; // for webkit and firefox

            /** create the treeWalker to traverse only elements **/
            var treeWalker = document.createTreeWalker(root, NodeFilter.SHOW_ELEMENT, filter, false);

            /** traverse all elements using treeWalker.nextNode(). First node is the root **/
            do {
                var style = window.getComputedStyle(treeWalker.currentNode, null);
                var computedProps = style.getPropertyValue(TRANSITION_PROPERTY).split(', ');
                var computedDurations = style.getPropertyValue(TRANSITION_DURATION).split(', ');

                /** push all props with duration which is not 0s **/
                computedDurations.forEach(function (duration, index) {
                    duration !== '0s' && queue.push(computedProps[index]);
                });
            } while (treeWalker.nextNode()); // iterate until no next node

            // no transitions, fire (almost) immediately
            if (queue.length === 0) {

                setTimeout(function () {
                    $node.trigger('transitionsComplete');
                }, 5);

                return; // return out of the function to skip the transitions block
            }

            // there are transitions
            $node.on('webkitTransitionEnd.x transitionend.x', function (e) {
                var propertyName = e.originalEvent.propertyName;
                var indexOfProp = queue.indexOf(propertyName);

                queue.splice(indexOfProp, 1);

                if (queue.length < 1) {
                    console.log('Transitions Complete');
                    $node.trigger('transitionsComplete');
                }
            });

        },

        teardown: function (namespaces) {
            $(this).off('.x');
        }

    };
})(jQuery);

Answer 3

$(function() {

  var div = $("div"),
    p = $("p"),
    start = new Date().getTime();
  console.log("-- start --");
  div.addClass("visible");

  var n = 0
  , transitions = [];
  div.on({
    "transitionend": function(e) {
      ++n;
      transitions.push({
        "element": e.originalEvent.srcElement,
        "property": e.originalEvent.propertyName,
        "duration": e.originalEvent.elapsedTime
      });
      var container = $(this).css("transition").split(","),
        elems = $(p, this).css("transition").split(",");
      if (container.length === 1 && n === elems.length) {
        $(this).trigger("transitionComplete", [transitions])
      }
    },
    "transitionComplete": function(e, tx) {
      console.log(e.type, this, (new Date().getTime() - start) / 1000, tx);
      alert(e.type);
    }
  });

});

p {
  opacity: 0;
  transition: opacity 10s, transform 5s;
  background: red;
  width: 50px;
  height: 50px;
  margin: 100px;
}
div.visible p {
  opacity: 1;
  transform: scale(1.5);
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

<div>
  <p></p>
</div>

jsfiddle http://jsfiddle.net/nf8gvbuo/1/

Answer 4

if($('div').one('webkitTransitionEnd otransitionend oTransitionEnd msTransitionEnd transitionend')) {
  $('div').one('webkitTransitionEnd otransitionend oTransitionEnd msTransitionEnd transitionend', function(e) {
    console.log("Fire after transitions");
  });
} else {
  console.log("Fire immediately if there are no transitions");
}

我相信有人会解释为什么这样的实现不起作用，但也许它会提供一些灵感/讨论。

https://jsfiddle.net/nf8gvbuo/16/

始终触发且仅触发一次的 "transitionend" 事件

A "transitionend" event that always fires, and once only

javascript

jquery

css-transitions

jquery-events