deferred

@page Deferreds Deferreds @parent Tutorial 7

@body Deferreds in CanJS are explained in greater detail in the API. Below is a quick tour through can.Deferred, which should look familiar to you if you have experience with the Deferred pattern.

@codestart // Create a new Deferred: var dfd = new can.Deferred();

// Add a done callback: dfd.done(function(foo) { console.log('Resolved!'); }); // Add a fail callback: dfd.fail(function(bar) { console.log('Rejected!'); }); // Add a callback that fires whether the // Deferred is resolve or rejected. dfd.always(function(obj) { console.log('Apathetic!'); });

var dfd2 = new can.Deferred(); // Add done and fail callbacks: dfd2.then(functon(foo) { console.log('Also resolved.'); }, function(bar) { console.log('Also rejected.'); });

// Create a Deferred that resolves when // all passed Deferreds resolve: var endDfd = can.when(dfd, dfd2).then(function() { console.log('I open at the close.'); });

// Resolve a Deferred (and call all its done callbacks): dfd.resolve('foo');

// Reject a Deferred (and call all its fail callbacks): dfd.reject('bar'); @codeend