deferred = jQuery.Deferred(),
completeDeferred = jQuery._Deferred(),
jqXHR ={/**/}
//....
deferred.promise( jqXHR );
jqXHR.success = jqXHR.done;
jqXHR.error = jqXHR.fail;
jqXHR.complete = completeDeferred.done;
jQuery1.7，从deferred模块中分化出callback模块，其实就是之前的_Deferred的增强版，添加去重，锁定，return false时中断执行下一个回调，清空等功能。
复制代码 代码如下:
(function( jQuery ) {
// String to Object flags format cache
var flagsCache = {};
// Convert String-formatted flags into Object-formatted ones and store in cache
function createFlags( flags ) {
var object = flagsCache[ flags ] = {},
i, length;
flags = flags.split( /\s+/ );
for ( i = 0, length = flags.length; i < length; i++ ) {
object[ flags[i] ] = true;
}
return object;
}
/*
* Create a callback list using the following parameters:
*
* flags: an optional list of space-separated flags that will change how
* the callback list behaves
*
* By default a callback list will act like an event callback list and can be
* "fired" multiple times.
*
* Possible flags:
*
* once: will ensure the callback list can only be fired once (like a Deferred)
*
* memory: will keep track of previous values and will call any callback added
* after the list has been fired right away with the latest "memorized"
* values (like a Deferred)
*
* unique: will ensure a callback can only be added once (no duplicate in the list)
*
* stopOnFalse: interrupt callings when a callback returns false
*
*/
jQuery.Callbacks = function( flags ) {
// Convert flags from String-formatted to Object-formatted
// (we check in cache first)
flags = flags ? ( flagsCache[ flags ] || createFlags( flags ) ) : {};
var // Actual callback list
list = [],
// Stack of fire calls for repeatable lists
stack = [],
// Last fire value (for non-forgettable lists)
memory,
// Flag to know if list is currently firing
firing,
// First callback to fire (used internally by add and fireWith)
firingStart,
// End of the loop when firing
firingLength,
// Index of currently firing callback (modified by remove if needed)
firingIndex,
// Add one or several callbacks to the list
add = function( args ) {
var i,
length,
elem,
type,
actual;
for ( i = 0, length = args.length; i < length; i++ ) {
elem = args[ i ];
type = jQuery.type( elem );
if ( type =https://www.jb51.net/article/== "array" ) {
// Inspect recursively
add( elem );
} else if ( type =https://www.jb51.net/article/== "function" ) {
// Add if not in unique mode and callback is not in
if ( !flags.unique || !self.has( elem ) ) {
list.push( elem );
}
}
}
},
// Fire callbacks
fire = function( context, args ) {
args = args || [];
memory = !flags.memory || [ context, args ];
firing = true;
firingIndex = firingStart || 0;
firingStart = 0;
firingLength = list.length;
for ( ; list && firingIndex < firingLength; firingIndex++ ) {
if ( list[ firingIndex ].apply( context, args ) =https://www.jb51.net/article/== 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 =https://www.jb51.net/article/== true ) {
self.disable();
} else {
list = [];
}
}
},
// Actual Callbacks object
self = {
// Add a callback or a collection of callbacks to the list
add: function() {
if ( list ) {
var length = list.length;
add( arguments );
// Do we need to add the callbacks to the
// current firing batch?
if ( firing ) {
firingLength = list.length;
// With memory, if we're not firing then
// we should call right away, unless previous
// firing was halted (stopOnFalse)
} else if ( memory && memory !== true ) {
firingStart = length;
fire( memory[ 0 ], memory[ 1 ] );
}
}
return this;
},
// Remove a callback from the list
remove: function() {
if ( list ) {
var args = arguments,
argIndex = 0,
argLength = args.length;
for ( ; argIndex < argLength ; argIndex++ ) {
for ( var i = 0; i < list.length; i++ ) {
if ( args[ argIndex ] =https://www.jb51.net/article/== list[ i ] ) {
// Handle firingIndex and firingLength
if ( firing ) {
if ( i <= firingLength ) {
firingLength--;
if ( i <= firingIndex ) {
firingIndex--;
}
}
}
// Remove the element
list.splice( i--, 1 );
// If we have some unicity property then
// we only need to do this once
if ( flags.unique ) {
break;
}
}
}
}
}
return this;
},
// Control if a given callback is in the list
has: function( fn ) {
if ( list ) {
var i = 0,
length = list.length;
for ( ; i < length; i++ ) {
if ( fn =https://www.jb51.net/article/== 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 =https://www.jb51.net/article/== 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。
复制代码 代码如下: