promise test

promise

function log (str) {
	document.body.innerHTML += str + '<br/>';
}
 
function Promise (func) {
	var z = this;
	this._thens = [];
 
	function resolve () {
		var args = Array.prototype.slice.call(arguments);
		var fun = z._thens.shift();
 
		if (fun) {
			var p = fun.apply(null, args);

			if (p instanceof Promise) {
				p._thens = z._thens;
			} else {
				var promise = new Promise(function(resolve) {
					setTimeout(function () {
						resolve(p);
					});
				});

				promise._thens = z._thens;
			}
		}
	}
 
	func.call(null, resolve);
}
 
 
Promise.prototype.then = function (fun) {
	this._thens.push(fun);
 
	return this;
};

Promise.resolve = function () {
	var args = Array.prototype.slice.call(arguments);

	var promise = new Promise(function(resolve){		
			resolve.apply(null, args);
	});

	return promise;
};

Promise.all = function (promises) {
	var len = promises.length;
	var defer = Promise.deferred();
	var results = [];

	for(var i = 0; i < len; i++) {
		(function (i) {
			var p = promises[i];
		p.then(function (r) {
			results[i] = r;

			if (results.length === len) {
				defer.resolve(results);
			}
		});
		})(i);	
	}

	return defer.promise;
};

Promise.any = function (promises) {
	var len = promises.length;
	var defer = Promise.deferred();
	var results = [];

	for(var i = 0; i < len; i++) {
		(function (i) {
			var p = promises[i];
		p.then(function (r) {
			results[i] = r;

			if (results.length > 0) {
				defer.resolve(r);
			}
		});
		})(i);	
	}

	return defer.promise;
};

Promise.queue = function (funcs) {
	var temp_p = funcs[0]();

	for (var i = 1, len = funcs.length;i < len; i++) {
		(function (i) {
			temp_p.then(funcs[i]);
		})(i);
	}

	return temp_p;
};

Promise.deferred = function () {
	var defer = {};
	defer.promise = new Promise(function (resolve) {
		defer.resolve = resolve;
	});

	return defer;
};
 
function a1 () {
	var promise = new Promise (function (resolve) {
		setTimeout(function () {
			log('a1');
			resolve('a1');
		},2000);
	});
 
	return promise;
}

function a2 () {
	var defer = Promise.deferred();
	setTimeout(function () {
		log('a2');
		defer.resolve('a2');
	}, 1000);

	return defer.promise;
}
 
function b (txt) {
	return txt + "b";
   
} 
 
function c (txt) {
	return new Promise (function (resolve) {
		setTimeout(function () {
			resolve(txt + 'c');
		},1000);
	})
}

function d (txt) {
	log(txt + "d");

	return txt + "d";
} 

function e (txt) {
	log(txt + 'e');
}

// test
var test;
//a().then(b).then(c).then(d).then(e);
Promise.queue([a1,a2,c]).then(function (arr) {
	console.log(arr.length, arr);
	test = arr; 
});