Add timeout function to limit processing time

test/unit/timeout.js

@@ -0,0 +1,26 @@
+'use strict';
+
+const assert = require('assert');
+
+const sharp = require('../../');
+const fixtures = require('../fixtures');
+
+describe('Timeout', function () {
+  it('Will timeout after 1s when performing slow blur operation', () => assert.rejects(
+    () => sharp(fixtures.inputJpg)
+      .blur(100)
+      .timeout({ seconds: 1 })
+      .toBuffer(),
+    /timeout: [0-9]+% complete/
+  ));
+
+  it('invalid object', () => assert.throws(
+    () => sharp().timeout('fail'),
+    /Expected object for options but received fail of type string/
+  ));
+
+  it('invalid seconds', () => assert.throws(
+    () => sharp().timeout({ seconds: 'fail' }),
+    /Expected integer between 0 and 3600 for seconds but received fail of type string/
+  ));
+});