blob: b0ffe4a8583fccef1e273f3a5206a1d71e32d6ba [file] [log] [blame]
var enqueue = function (callback) {
//process.nextTick(callback); // NodeJS
setTimeout(callback, 1); // Naïve browser solution
};
var isPromise = function (value) {
return value && typeof value.then === "function";
};
var defer = function () {
var pending = [], value;
return {
resolve: function (_value) {
if (pending) {
value = ref(_value);
for (var i = 0, ii = pending.length; i < ii; i++) {
// XXX
enqueue(function () {
value.then.apply(value, pending[i]);
});
}
pending = undefined;
}
},
promise: {
then: function (_callback, _errback) {
var result = defer();
_callback = _callback || function (value) {
return value;
};
_errback = _errback || function (reason) {
return reject(reason);
};
var callback = function (value) {
result.resolve(_callback(value));
};
var errback = function (reason) {
result.resolve(_errback(reason));
};
if (pending) {
pending.push([callback, errback]);
} else {
// XXX
enqueue(function () {
value.then(callback, errback);
});
}
return result.promise;
}
}
};
};
var ref = function (value) {
if (value && value.then)
return value;
return {
then: function (callback) {
var result = defer();
// XXX
enqueue(function () {
result.resolve(callback(value));
});
return result.promise;
}
};
};
var reject = function (reason) {
return {
then: function (callback, errback) {
var result = defer();
// XXX
enqueue(function () {
result.resolve(errback(reason));
});
return result.promise;
}
};
};
var when = function (value, _callback, _errback) {
var result = defer();
var done;
_callback = _callback || function (value) {
return value;
};
_errback = _errback || function (reason) {
return reject(reason);
};
// XXX
var callback = function (value) {
try {
return _callback(value);
} catch (reason) {
return reject(reason);
}
};
var errback = function (reason) {
try {
return _errback(reason);
} catch (reason) {
return reject(reason);
}
};
enqueue(function () {
ref(value).then(function (value) {
if (done)
return;
done = true;
result.resolve(ref(value).then(callback, errback));
}, function (reason) {
if (done)
return;
done = true;
result.resolve(errback(reason));
});
});
return result.promise;
};