1 // Copyright 2014 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 // Flags: --harmony-arrow-functions 6 7 // Arrow functions are like functions, except they throw when using the 8 // "new" operator on them. 9 assertEquals("function", typeof (() => {})); 10 assertEquals(Function.prototype, Object.getPrototypeOf(() => {})); 11 assertThrows(function() { new (() => {}); }, TypeError); 12 assertFalse("prototype" in (() => {})); 13 14 // Check the different syntax variations 15 assertEquals(1, (() => 1)()); 16 assertEquals(2, (a => a + 1)(1)); 17 assertEquals(3, (() => { return 3; })()); 18 assertEquals(4, (a => { return a + 3; })(1)); 19 assertEquals(5, ((a, b) => a + b)(1, 4)); 20 assertEquals(6, ((a, b) => { return a + b; })(1, 5)); 21 22 // The following are tests from: 23 // http://wiki.ecmascript.org/doku.php?id=harmony:arrow_function_syntax 24 25 // Empty arrow function returns undefined 26 var empty = () => {}; 27 assertEquals(undefined, empty()); 28 29 // Single parameter case needs no parentheses around parameter list 30 var identity = x => x; 31 assertEquals(empty, identity(empty)); 32 33 // No need for parentheses even for lower-precedence expression body 34 var square = x => x * x; 35 assertEquals(9, square(3)); 36 37 // Parenthesize the body to return an object literal expression 38 var key_maker = val => ({key: val}); 39 assertEquals(empty, key_maker(empty).key); 40 41 // Statement body needs braces, must use 'return' explicitly if not void 42 var evens = [0, 2, 4, 6, 8]; 43 assertEquals([1, 3, 5, 7, 9], evens.map(v => v + 1)); 44 45 var fives = []; 46 [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].forEach(v => { 47 if (v % 5 === 0) fives.push(v); 48 }); 49 assertEquals([5, 10], fives); 50
