jquery1.7.2的源码分析$.Deferred

Posted 2020-08-26 犹记惊鸿照影（JS）

例子的详细讲解

Filter Resolve
 

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 = [];
            }
        }
    }