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 }); 84
