added timeout

README.md

@@ -20,23 +20,37 @@ Can be used as a yieldable with [co](https://github.com/tj/co) or in [koa](koajs
 Basic example:
 
 ```javascript
-var wait = require('wait-then');
+var wait = require('wait-then'),
+    timeout = wait.timeout;
 
 wait(2000).then(function() {
     console.log('This is logged after 2 seconds');
 });
+
+timeout(2000).catch(e) {
+    console.log('This is logged after 2 seconds');
+}
 ```
 
 Example with `co`:
 
 ```javascript
 var wait = require('wait-then'),
+    timeout = wait.timeout,
     co = require('co');
 
 co(function *() {
     yield wait(1000);
     console.log('This is logged after 1 second');
 });
+
+co(function *() {
+    try {
+        yield timeout(1000);
+    } catch (e) {
+        console.log('This is logged after 1 second');
+    }
+});
 ```
 
 The generator function passed into `co`  can be yielded in a middleware in `koa`.

lib/index.js

@@ -6,4 +6,12 @@ module.exports = function(ms) {
 			resolve();
 		}, ms);
 	});
-};
+};
+
+module.exports.timeout = function(ms) {
+	return new Promise(function(resolve, reject) {
+		setTimeout(function() {
+			reject(new Error('TIMED OUT'));
+		}, ms);
+	});
+}

test/index.js

@@ -1,11 +1,12 @@
 "use strict";
 
 var co = require('co'),
-	wait = require('../lib');
+	wait = require('../lib'),
+	timeout = wait.timeout;
 
 require('chai').should();
 
-describe('wait-then', function() {
+describe('wait', function() {
 
 	it('should return an instance of Promise', function() {
 		(wait(1) instanceof Promise).should.be.true;
@@ -41,4 +42,45 @@ describe('wait-then', function() {
 		});
 	});
 
+});
+
+
+describe('timeout', function() {
+
+	it('should return an instance of Promise', function() {
+		(timeout(1) instanceof Promise).should.be.true;
+		(timeout(1).then instanceof Function).should.be.true;
+	});
+
+	it('should reject after the given time', function(done) {
+		var t = 100,
+			now = Date.now();
+
+		timeout(t)
+			.then(function() {
+				done(new Error('resolved instead of rejecting'));
+			})
+			.catch(function(e) {
+				(Date.now() - now).should.be.at.least(t).and.at.most(t * 1.1); // 10% margin
+				e.message.should.equal('TIMED OUT');
+				done();
+			});
+	});
+
+	it('should work with co', function(done) {
+		co(function *() {
+			var t = 200,
+				now = Date.now();
+
+			try {
+				yield timeout(t);
+				done(new Error('resolved instead of rejecting'));
+			} catch (e) { // because the error is thrown in the context of setTimeout and cannot be caught by 'it' otherwise
+				(Date.now() - now).should.be.at.least(t).and.at.most(t * 1.1); // 10% margin
+				e.message.should.equal('TIMED OUT');
+				done();
+			}
+		});
+	});
+
 });