Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 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 | // Arrow functions are like functions, except they throw when using the |
| 6 | // "new" operator on them. |
| 7 | assertEquals("function", typeof (() => {})); |
| 8 | assertEquals(Function.prototype, Object.getPrototypeOf(() => {})); |
| 9 | assertThrows(function() { new (() => {}); }, TypeError); |
| 10 | assertFalse("prototype" in (() => {})); |
| 11 | |
| 12 | // Check the different syntax variations |
| 13 | assertEquals(1, (() => 1)()); |
| 14 | assertEquals(2, (a => a + 1)(1)); |
| 15 | assertEquals(3, (() => { return 3; })()); |
| 16 | assertEquals(4, (a => { return a + 3; })(1)); |
| 17 | assertEquals(5, ((a, b) => a + b)(1, 4)); |
| 18 | assertEquals(6, ((a, b) => { return a + b; })(1, 5)); |
| 19 | |
| 20 | // The following are tests from: |
| 21 | // http://wiki.ecmascript.org/doku.php?id=harmony:arrow_function_syntax |
| 22 | |
| 23 | // Empty arrow function returns undefined |
| 24 | var empty = () => {}; |
| 25 | assertEquals(undefined, empty()); |
| 26 | |
| 27 | // Single parameter case needs no parentheses around parameter list |
| 28 | var identity = x => x; |
| 29 | assertEquals(empty, identity(empty)); |
| 30 | |
| 31 | // No need for parentheses even for lower-precedence expression body |
| 32 | var square = x => x * x; |
| 33 | assertEquals(9, square(3)); |
| 34 | |
| 35 | // Parenthesize the body to return an object literal expression |
| 36 | var key_maker = val => ({key: val}); |
| 37 | assertEquals(empty, key_maker(empty).key); |
| 38 | |
| 39 | // Statement body needs braces, must use 'return' explicitly if not void |
| 40 | var evens = [0, 2, 4, 6, 8]; |
| 41 | assertEquals([1, 3, 5, 7, 9], evens.map(v => v + 1)); |
| 42 | |
| 43 | var fives = []; |
| 44 | [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].forEach(v => { |
| 45 | if (v % 5 === 0) fives.push(v); |
| 46 | }); |
| 47 | assertEquals([5, 10], fives); |
| 48 | |
| 49 | (function testRestrictedFunctionPropertiesStrict() { |
| 50 | var arrowFn = () => { "use strict"; }; |
| 51 | assertFalse(arrowFn.hasOwnProperty("arguments")); |
| 52 | assertThrows(function() { return arrowFn.arguments; }, TypeError); |
| 53 | assertThrows(function() { arrowFn.arguments = {}; }, TypeError); |
| 54 | |
| 55 | assertFalse(arrowFn.hasOwnProperty("caller")); |
| 56 | assertThrows(function() { return arrowFn.caller; }, TypeError); |
| 57 | assertThrows(function() { arrowFn.caller = {}; }, TypeError); |
| 58 | })(); |
| 59 | |
| 60 | |
| 61 | (function testRestrictedFunctionPropertiesSloppy() { |
| 62 | var arrowFn = () => {}; |
| 63 | assertFalse(arrowFn.hasOwnProperty("arguments")); |
| 64 | assertThrows(function() { return arrowFn.arguments; }, TypeError); |
| 65 | assertThrows(function() { arrowFn.arguments = {}; }, TypeError); |
| 66 | |
| 67 | assertFalse(arrowFn.hasOwnProperty("caller")); |
| 68 | assertThrows(function() { return arrowFn.caller; }, TypeError); |
| 69 | assertThrows(function() { arrowFn.caller = {}; }, TypeError); |
| 70 | })(); |
| 71 | |
| 72 | |
| 73 | // v8:4474 |
| 74 | (function testConciseBodyReturnsRegexp() { |
| 75 | var arrow1 = () => /foo/ |
| 76 | var arrow2 = () => /foo/; |
| 77 | var arrow3 = () => /foo/i |
| 78 | var arrow4 = () => /foo/i; |
| 79 | assertEquals(arrow1.toString(), "() => /foo/"); |
| 80 | assertEquals(arrow2.toString(), "() => /foo/"); |
| 81 | assertEquals(arrow3.toString(), "() => /foo/i"); |
| 82 | assertEquals(arrow4.toString(), "() => /foo/i"); |
| 83 | }); |