for ( ; i < length; i++ ) {
if ( fn === list[ i ] ) {
return true;
}
}
}
return false;
},
// Remove all callbacks from the list
empty: function() {
list = [];
return this;
},
// Have the list do nothing anymore
disable: function() {
list = stack = memory = undefined;
return this;
},
// Is it disabled?
disabled: function() {
return !list;
},
// Lock the list in its current state
lock: function() {
stack = undefined;
if ( !memory || memory === true ) {
self.disable();
}
return this;
},
// Is it locked?
locked: function() {
return !stack;
},
// Call all callbacks with the given context and arguments
fireWith: function( context, args ) {
if ( stack ) {
if ( firing ) {
if ( !flags.once ) {
stack.push( [ context, args ] );
}
} else if ( !( flags.once && memory ) ) {
fire( context, args );
}
}
return this;
},
// Call all the callbacks with the given arguments
fire: function() {
self.fireWith( this, arguments );
return this;
},
// To know if the callbacks have already been called at least once
fired: function() {
return !!memory;
}
};
return self;
};
})( jQuery );
这期间有还个小插曲，jQuery团队还想增加一个叫Topic的模块，内置发布者订阅者机制，但这封装太溥了，结果被否决。
(function( jQuery ) {
var topics = {},
sliceTopic = [].slice;
jQuery.Topic = function( id ) {
var callbacks,
method,
topic = id && topics[ id ];
if ( !topic ) {
callbacks = jQuery.Callbacks();
topic = {
publish: callbacks.fire,
subscribe: callbacks.add,
unsubscribe: callbacks.remove
};
if ( id ) {
topics[ id ] = topic;
}
}
return topic;
};
jQuery.extend({
subscribe: function( id ) {
var topic = jQuery.Topic( id ),
args = sliceTopic.call( arguments, 1 );
topic.subscribe.apply( topic, args );
return {
topic: topic,
args: args
};
},
unsubscribe: function( id ) {
var topic = id && id.topic || jQuery.Topic( id );
topic.unsubscribe.apply( topic, id && id.args ||
sliceTopic.call( arguments, 1 ) );
},
publish: function( id ) {
var topic = jQuery.Topic( id );
topic.publish.apply( topic, sliceTopic.call( arguments, 1 ) );
}
});
})( jQuery );
虽然把大量代码移动callbacks，但1.7的Deferred却一点没有没变小，它变得更重型，它由三个函数列队组成了。并且返回的是Promise对象，比原来多出了pipe, state, progress, always方法。ajax那边就变成这样：
deferred = jQuery.Deferred(),
completeDeferred = jQuery.Callbacks( “once memory” ),
deferred.promise( jqXHR );
jqXHR.success = jqXHR.done;
jqXHR.error = jqXHR.fail;
jqXHR.complete = completeDeferred.add;
queue那边也没变多少。
