feat: timeout promise extension

README.md

@@ -651,6 +651,32 @@ promise.spread(function (a, b) {
 });
 ```
 
+#### timeout
+
+Resolve with rejection ("Operation timeout" error with `DEFERRED_TIMEOUT` code), if given promise
+won't settle with resolved value within given _timeout_
+
+```javascript
+var deferred = new Deferred();
+
+deferred.promise.timeout(30).done(function (value) {
+	console.log("Never called");
+}, function () {
+	console.log("Rejected after 30 seconds");
+});
+
+deferred = new Deferred();
+deferred.promise.timeout(30).done(function (value) {
+	console.log("Resolved with", value); // Resolved with true
+}, function () {}
+	console.log("Never called");
+});
+setTimeout(function () {
+	deferred.resolve(true);
+}, 10);
+
+```
+
 ### Debugging
 
 #### Monitoring unresolved promises
@@ -771,4 +797,4 @@ __Covered by over 300 unit tests__
 
 
 ## License
-[![FOSSA Status](https://app.fossa.io/api/projects/git%2Bgit.luolix.top%2Fmedikoo%2Fdeferred.svg?type=large)](https://app.fossa.io/projects/git%2Bgit.luolix.top%2Fmedikoo%2Fdeferred?ref=badge_large)
+[![FOSSA Status](https://app.fossa.io/api/projects/git%2Bgit.luolix.top%2Fmedikoo%2Fdeferred.svg?type=large)](https://app.fossa.io/projects/git%2Bgit.luolix.top%2Fmedikoo%2Fdeferred?ref=badge_large)

ext/promise/timeout.js

@@ -0,0 +1,38 @@
+// 'timeout' - Promise extension
+//
+// promise.timeout(ms)
+//
+// Resolves with resolution value of context promise assuming it settles before timeout time passes
+// Otherwise resolves with timeout rejection
+
+"use strict";
+
+var customError   = require("es5-ext/error/custom")
+  , isValue       = require("es5-ext/object/is-value")
+  , nextTick      = require("next-tick")
+  , ensureTimeout = require("timers-ext/valid-timeout")
+  , deferred      = require("../../deferred");
+
+deferred.extend(
+	"timeout",
+	function (timeout) {
+		var def;
+		var callback = function () {
+			if (this.resolved) return;
+			def.reject(customError("Operation timeout", "DEFERRED_TIMEOUT"));
+		}.bind(this);
+		if (isValue(timeout)) setTimeout(callback, ensureTimeout(timeout));
+		else nextTick(callback);
+		if (!this.pending) this.pending = [];
+		def = deferred();
+		this.pending.push("timeout", [def.promise, def.resolve]);
+		return def.promise;
+	},
+	function (promise, resolve) {
+		if (!promise.resolved) resolve(this);
+	},
+	function (timeout) {
+		if (isValue(timeout)) ensureTimeout(timeout);
+		return this;
+	}
+);

index.js

@@ -40,3 +40,4 @@ require("./ext/promise/map");
 require("./ext/promise/reduce");
 require("./ext/promise/spread");
 require("./ext/promise/some");
+require("./ext/promise/timeout");

test/ext/promise/timeout.js

@@ -0,0 +1,19 @@
+"use strict";
+
+var Deferred = require("../../../deferred");
+
+module.exports = function (t, a, d) {
+	var x = {}, deferred = new Deferred(), promise = deferred.promise.timeout(10);
+	deferred.resolve(x);
+	setTimeout(function () {
+		a(promise.value, x);
+		deferred = new Deferred();
+		promise = deferred.promise.timeout(10);
+		setTimeout(function () {
+			deferred.resolve();
+			a(promise.failed, true);
+			a(promise.value.code, "DEFERRED_TIMEOUT");
+			d();
+		}, 20);
+	}, 20);
+};

test/index.js

@@ -36,7 +36,8 @@ module.exports = {
 			"find",
 			"map",
 			"reduce",
-			"some"
+			"some",
+			"timeout"
 		]
 	),
 	"isPromise": function (t, a) {