例子的详细讲解

Filter Resolve
 
<script>      var filterResolve = function() {          var defer = $.Deferred(),                  filtered = defer.then(function( value ) {                      return value * 2;                  });          defer.resolve( 5 );          filtered.done(function( value ) {              $( "p" ).html( "Value is ( 2*5 = ) 10: " + value );          });      };      $( "button" ).on( "click", filterResolve );</script>

上面的的代码是怎么运行的呢

点击button的先执行 $.Deferred()，得到具有很多方法的defer

defer.resolve( 5 );

var doneList = jQuery.Callbacks( "once memory" ),failList = jQuery.Callbacks( "once memory" ),progressList = jQuery.Callbacks( "memory" ),state = "pending";lists = {resolve: doneList,reject: failList,notify: progressList}for ( key in lists ) {deferred[ key ] = lists[ key ].fire;deferred[ key + "With" ] = lists[ key ].fireWith;}//根据上面的代码可得//deferred[ ‘resolve‘]=lists[ ‘resolve‘].fire;//deferred[ ‘resolveWidth‘]=lists[ ‘resolve‘].fireWith;//deferred[ ‘reject‘]=lists[ ‘reject‘].fire;//deferred[ ‘rejectWidth‘]=lists[ ‘reject‘].fireWith;//deferred[ ‘notify‘]=lists[ ‘notify‘].fire;//deferred[ ‘notifyWidth‘]=lists[ ‘notify‘].fireWith;//因此resolve( 5 )执行了

fire: function() {    self.fireWith( this, arguments );    return this;},fireWith: function( context, args ) {//stack=[];为true；firing 为false；flag={}    if ( stack ) {        if ( firing ) {            if ( !flags.once ) {                stack.push( [ context, args ] );            }//memory =undefined        } else if ( !( flags.once && memory ) ) {            fire( context, args );        }    }    return this;}

fire = function( context, args ) {        args = args || [];//memory = [ context, args ];即为self，和5        memory = !flags.memory || [ context, args ];        fired = true;        firing = true;        firingIndex = firingStart || 0;        firingStart = 0;        firingLength = list.length;        for ( ; list && firingIndex < firingLength; firingIndex++ ) {//函数执行后为false并且flags.stopOnFalse 为true时memory = true;//注意这里执行了函数            if ( list[ firingIndex ].apply( context, args ) === false && flags.stopOnFalse ) {                memory = true; // Mark as halted                break;            }        }        firing = false;        if ( list ) {            if ( !flags.once ) {                if ( stack && stack.length ) {                    memory = stack.shift();                    self.fireWith( memory[ 0 ], memory[ 1 ] );                }            } else if ( memory === true ) {                self.disable();            } else {//最终又把list函数组给赋值为空                list = [];            }        }    }

jquery1.7.2的源码分析（三）$.Deferred