Q promise: are callbacks invoked in the same order

问题:

I'm using the Q promise library. My code relies on the fact that the callbacks for a single promise are executed in the same order as they were registered.

http://jsfiddle.net/HgYtK/1/

var deferred = Q.defer();
var promise = deferred.promise;

['first', 'second', 'third'].forEach(function (position) {
  promise.then(function () {
    alert(position);
  });
});

deferred.resolve();

This does produce the correct result, but I don't know if it's part of the spec or a happy coincidence that could break down the line.

回答1:

From the Promises/A+ Spec

2.2.6.1

If/when promise is fulfilled, respective onFulfilled callbacks must execute in the order of their originating calls to then.