deferred.js
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define( [
"./core",
"./var/slice",
"./callbacks"
], function( jQuery, slice ) {
"use strict";
function Identity( v ) {
return v;
}
function Thrower( ex ) {
throw ex;
}
function adoptValue( value, resolve, reject, noValue ) {
var method;
try {
// Check for promise aspect first to privilege synchronous behavior
if ( value && jQuery.isFunction( ( method = value.promise ) ) ) {
method.call( value ).done( resolve ).fail( reject );
// Other thenables
} else if ( value && jQuery.isFunction( ( method = value.then ) ) ) {
method.call( value, resolve, reject );
// Other non-thenables
} else {
// Control `resolve` arguments by letting Array#slice cast boolean `noValue` to integer:
// * false: [ value ].slice( 0 ) => resolve( value )
// * true: [ value ].slice( 1 ) => resolve()
resolve.apply( undefined, [ value ].slice( noValue ) );
}
// For Promises/A+, convert exceptions into rejections
// Since jQuery.when doesn't unwrap thenables, we can skip the extra checks appearing in
// Deferred#then to conditionally suppress rejection.
} catch ( value ) {
// Support: Android 4.0 only
// Strict mode functions invoked without .call/.apply get global-object context
reject.apply( undefined, [ value ] );
}
}
jQuery.extend( {
Deferred: function( func ) {
var tuples = [
// action, add listener, callbacks,
// ... .then handlers, argument index, [final state]
[ "notify", "progress", jQuery.Callbacks( "memory" ),
jQuery.Callbacks( "memory" ), 2 ],
[ "resolve", "done", jQuery.Callbacks( "once memory" ),
jQuery.Callbacks( "once memory" ), 0, "resolved" ],
[ "reject", "fail", jQuery.Callbacks( "once memory" ),
jQuery.Callbacks( "once memory" ), 1, "rejected" ]
],
state = "pending",
promise = {
state: function() {
return state;
},
always: function() {
deferred.done( arguments ).fail( arguments );
return this;
},
"catch": function( fn ) {
return promise.then( null, fn );
},
// Keep pipe for back-compat
pipe: function( /* fnDone, fnFail, fnProgress */ ) {
var fns = arguments;
return jQuery.Deferred( function( newDefer ) {
jQuery.each( tuples, function( i, tuple ) {
// Map tuples (progress, done, fail) to arguments (done, fail, progress)
var fn = jQuery.isFunction( fns[ tuple[ 4 ] ] ) && fns[ tuple[ 4 ] ];
// deferred.progress(function() { bind to newDefer or newDefer.notify })
// deferred.done(function() { bind to newDefer or newDefer.resolve })
// deferred.fail(function() { bind to newDefer or newDefer.reject })
deferred[ tuple[ 1 ] ]( function() {
var returned = fn && fn.apply( this, arguments );
if ( returned && jQuery.isFunction( returned.promise ) ) {
returned.promise()
.progress( newDefer.notify )
.done( newDefer.resolve )
.fail( newDefer.reject );
} else {
newDefer[ tuple[ 0 ] + "With" ](
this,
fn ? [ returned ] : arguments
);
}
} );
} );
fns = null;
} ).promise();
},
then: function( onFulfilled, onRejected, onProgress ) {
var maxDepth = 0;
function resolve( depth, deferred, handler, special ) {
return function() {
var that = this,
args = arguments,
mightThrow = function() {
var returned, then;
// Support: Promises/A+ section 2.3.3.3.3
// https://promisesaplus.com/#point-59
// Ignore double-resolution attempts
if ( depth < maxDepth ) {
return;
}
returned = handler.apply( that, args );
// Support: Promises/A+ section 2.3.1
// https://promisesaplus.com/#point-48
if ( returned === deferred.promise() ) {
throw new TypeError( "Thenable self-resolution" );
}
// Support: Promises/A+ sections 2.3.3.1, 3.5
// https://promisesaplus.com/#point-54
// https://promisesaplus.com/#point-75
// Retrieve `then` only once
then = returned &&
// Support: Promises/A+ section 2.3.4
// https://promisesaplus.com/#point-64
// Only check objects and functions for thenability
( typeof returned === "object" ||
typeof returned === "function" ) &&
returned.then;
// Handle a returned thenable
if ( jQuery.isFunction( then ) ) {
// Special processors (notify) just wait for resolution
if ( special ) {
then.call(
returned,
resolve( maxDepth, deferred, Identity, special ),
resolve( maxDepth, deferred, Thrower, special )
);
// Normal processors (resolve) also hook into progress
} else {
// ...and disregard older resolution values
maxDepth++;
then.call(
returned,
resolve( maxDepth, deferred, Identity, special ),
resolve( maxDepth, deferred, Thrower, special ),
resolve( maxDepth, deferred, Identity,
deferred.notifyWith )
);
}
// Handle all other returned values
} else {
// Only substitute handlers pass on context
// and multiple values (non-spec behavior)
if ( handler !== Identity ) {
that = undefined;
args = [ returned ];
}
// Process the value(s)
// Default process is resolve
( special || deferred.resolveWith )( that, args );
}
},
// Only normal processors (resolve) catch and reject exceptions
process = special ?
mightThrow :
function() {
try {
mightThrow();
} catch ( e ) {
if ( jQuery.Deferred.exceptionHook ) {
jQuery.Deferred.exceptionHook( e,
process.stackTrace );
}
// Support: Promises/A+ section 2.3.3.3.4.1
// https://promisesaplus.com/#point-61
// Ignore post-resolution exceptions
if ( depth + 1 >= maxDepth ) {
// Only substitute handlers pass on context
// and multiple values (non-spec behavior)
if ( handler !== Thrower ) {
that = undefined;
args = [ e ];
}
deferred.rejectWith( that, args );
}
}
};
// Support: Promises/A+ section 2.3.3.3.1
// https://promisesaplus.com/#point-57
// Re-resolve promises immediately to dodge false rejection from
// subsequent errors
if ( depth ) {
process();
} else {
// Call an optional hook to record the stack, in case of exception
// since it's otherwise lost when execution goes async
if ( jQuery.Deferred.getStackHook ) {
process.stackTrace = jQuery.Deferred.getStackHook();
}
window.setTimeout( process );
}
};
}
return jQuery.Deferred( function( newDefer ) {
// progress_handlers.add( ... )
tuples[ 0 ][ 3 ].add(
resolve(
0,
newDefer,
jQuery.isFunction( onProgress ) ?
onProgress :
Identity,
newDefer.notifyWith
)
);
// fulfilled_handlers.add( ... )
tuples[ 1 ][ 3 ].add(
resolve(
0,
newDefer,
jQuery.isFunction( onFulfilled ) ?
onFulfilled :
Identity
)
);
// rejected_handlers.add( ... )
tuples[ 2 ][ 3 ].add(
resolve(
0,
newDefer,
jQuery.isFunction( onRejected ) ?
onRejected :
Thrower
)
);
} ).promise();
},
// Get a promise for this deferred
// If obj is provided, the promise aspect is added to the object
promise: function( obj ) {
return obj != null ? jQuery.extend( obj, promise ) : promise;
}
},
deferred = {};
// Add list-specific methods
jQuery.each( tuples, function( i, tuple ) {
var list = tuple[ 2 ],
stateString = tuple[ 5 ];
// promise.progress = list.add
// promise.done = list.add
// promise.fail = list.add
promise[ tuple[ 1 ] ] = list.add;
// Handle state
if ( stateString ) {
list.add(
function() {
// state = "resolved" (i.e., fulfilled)
// state = "rejected"
state = stateString;
},
// rejected_callbacks.disable
// fulfilled_callbacks.disable
tuples[ 3 - i ][ 2 ].disable,
// progress_callbacks.lock
tuples[ 0 ][ 2 ].lock
);
}
// progress_handlers.fire
// fulfilled_handlers.fire
// rejected_handlers.fire
list.add( tuple[ 3 ].fire );
// deferred.notify = function() { deferred.notifyWith(...) }
// deferred.resolve = function() { deferred.resolveWith(...) }
// deferred.reject = function() { deferred.rejectWith(...) }
deferred[ tuple[ 0 ] ] = function() {
deferred[ tuple[ 0 ] + "With" ]( this === deferred ? undefined : this, arguments );
return this;
};
// deferred.notifyWith = list.fireWith
// deferred.resolveWith = list.fireWith
// deferred.rejectWith = list.fireWith
deferred[ tuple[ 0 ] + "With" ] = list.fireWith;
} );
// Make the deferred a promise
promise.promise( deferred );
// Call given func if any
if ( func ) {
func.call( deferred, deferred );
}
// All done!
return deferred;
},
// Deferred helper
when: function( singleValue ) {
var
// count of uncompleted subordinates
remaining = arguments.length,
// count of unprocessed arguments
i = remaining,
// subordinate fulfillment data
resolveContexts = Array( i ),
resolveValues = slice.call( arguments ),
// the master Deferred
master = jQuery.Deferred(),
// subordinate callback factory
updateFunc = function( i ) {
return function( value ) {
resolveContexts[ i ] = this;
resolveValues[ i ] = arguments.length > 1 ? slice.call( arguments ) : value;
if ( !( --remaining ) ) {
master.resolveWith( resolveContexts, resolveValues );
}
};
};
// Single- and empty arguments are adopted like Promise.resolve
if ( remaining <= 1 ) {
adoptValue( singleValue, master.done( updateFunc( i ) ).resolve, master.reject,
!remaining );
// Use .then() to unwrap secondary thenables (cf. gh-3000)
if ( master.state() === "pending" ||
jQuery.isFunction( resolveValues[ i ] && resolveValues[ i ].then ) ) {
return master.then();
}
}
// Multiple arguments are aggregated like Promise.all array elements
while ( i-- ) {
adoptValue( resolveValues[ i ], updateFunc( i ), master.reject );
}
return master.promise();
}
} );
return jQuery;
} );