Array.prototype.{every, filter, find, findIndex, forEach, map, some}: Use fresh primitive wrapper f…

test/mjsunit/array-iteration.js

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 50 matching lines @@
   // Respect holes.
   a = new Array(20);
   var count = 0;
   a[2] = 2;
   a[15] = 2;
   a[17] = 4;
   var a = a.filter(function(n) { count++; return n == 2; });
   assertEquals(3, count);
   for (var i in a) assertEquals(2, a[i]);
 
+  // When evaluating 'this', primitive values should be coerced to an object.

[wingo, 2014/09/23 18:39:01]

previous comment was more correct -- the wrapper happens when determining the
receiver for the function call, not when evaluating this within the function.

[Diego Pino, 2014/09/24 10:13:01]

Acknowledged.

+  // See ECMA-262, Annex C.
+  a = [];
+  [1, 2].filter(function() { a.push(this) }, "");
+  assertTrue(a[0] !== a[1]);
+
+  // When evaluating 'this', non-primitive values are not coerced to an object.
+  a = [];
+  [1, 2].filter(function() { a.push(this) }, {});
+  assertFalse(a[0] !== a[1]);
+
+  // In strict mode, when evaluating 'this', primitive values should not be
+  // coerced to an object.
+  a = [];
+  [1, 2].filter(function() { 'use strict'; a.push(this); }, "");

[wingo, 2014/09/23 18:39:01]

great test.

+  assertTrue(a[0] === "" && a[0] === a[1]);
+
 })();
 
 
 //
 // Array.prototype.forEach
 //
 (function() {
   // Simple use.
   var a = [0,1];
   var count = 0;
@@ skipping 21 matching lines @@
   assertEquals(2, count);
   assertArrayEquals([1,1,2,2], a);
 
   // Respect holes.
   a = new Array(20);
   count = 0;
   a[15] = 2;
   a.forEach(function(n) { count++; });
   assertEquals(1, count);
 
+  // When evaluating 'this', primitive values should be coerced to an object.
+  // See ECMA-262, Annex C.
+  a = [];
+  [1, 2].forEach(function() { a.push(this) }, "");
+  assertTrue(a[0] !== a[1]);
+
+  // When evaluating 'this', non-primitive values are not coerced to an object.
+  a = [];
+  [1, 2].forEach(function() { a.push(this) }, {});
+  assertFalse(a[0] !== a[1]);
+
+  // In strict mode, when evaluating 'this', primitive values should not be
+  // coerced to an object.
+  a = [];
+  [1, 2].forEach(function() { 'use strict'; a.push(this); }, "");
+  assertTrue(a[0] === "" && a[0] === a[1]);
+
 })();
 
 
 //
 // Array.prototype.every
 //
 (function() {
   // Simple use.
   var a = [0,1];
   assertFalse(a.every(function(n) { return n == 0 }));
@@ skipping 20 matching lines @@
   assertArrayEquals([1,1,2,2], a);
 
   // Respect holes.
   a = new Array(20);
   var count = 0;
   a[2] = 2;
   a[15] = 2;
   assertTrue(a.every(function(n) { count++; return n == 2; }));
   assertEquals(2, count);
 
+  // When evaluating 'this', primitive values should be coerced to an object.
+  // See ECMA-262, Annex C.
+  a = [];
+  [1, 2].every(function() { a.push(this); return true; }, "");
+  assertTrue(a[0] !== a[1]);
+
+  // When evaluating 'this', non-primitive values are not coerced to an object.
+  a = [];
+  [1, 2].every(function() { a.push(this); return true; }, {});
+  assertFalse(a[0] !== a[1]);
+
+  // In strict mode, when evaluating 'this', primitive values should not be
+  // coerced to an object.
+  a = [];
+  [1, 2].every(function() { 'use strict'; a.push(this); return true; }, "");
+  assertTrue(a[0] === "" && a[0] === a[1]);
+
 })();
 
 //
 // Array.prototype.map
 //
 (function() {
   var a = [0,1,2,3,4];
 
   // Simple use.
   var result = [1,2,3,4,5];
@@ skipping 17 matching lines @@
   result = [1,2,3,4,5];
   assertArrayEquals(result, a.map(function(n, index, array) { array.push(n); return n + 1;}));
   assertArrayEquals([0,1,2,3,4,0,1,2,3,4], a);
 
   // Respect holes.
   a = new Array(20);
   a[15] = 2;
   a = a.map(function(n) { return 2*n; });
   for (var i in a) assertEquals(4, a[i]);
 
+  // When evaluating 'this', primitive values should be coerced to an object.
+  // See ECMA-262, Annex C.
+  a = [];
+  [1, 2].map(function() { a.push(this) }, "");
+  assertTrue(a[0] !== a[1]);
+
+  // When evaluating 'this', non-primitive values are not coerced to an object.
+  a = [];
+  [1, 2].map(function() { a.push(this) }, {});
+  assertFalse(a[0] !== a[1]);
+
+  // In strict mode, when evaluating 'this', primitive values should not be
+  // coerced to an object.
+  a = [];
+  [1, 2].map(function() { 'use strict'; a.push(this); }, "");
+  assertTrue(a[0] === "" && a[0] === a[1]);
+
 })();
 
 //
 // Array.prototype.some
 //
 (function() {
   var a = [0,1,2,3,4];
 
   // Simple use.
   assertTrue(a.some(function(n) { return n == 3}));
@@ skipping 18 matching lines @@
 
   // Respect holes.
   a = new Array(20);
   var count = 0;
   a[2] = 42;
   a[10] = 2;
   a[15] = 42;
   assertTrue(a.some(function(n) { count++; return n == 2; }));
   assertEquals(2, count);
 
+  // When evaluating 'this', primitive values should be coerced to an object.
+  // See ECMA-262, Annex C.
+  a = [];
+  [1, 2].some(function() { a.push(this) }, "");
+  assertTrue(a[0] !== a[1]);
+
+  // When evaluating 'this', non-primitive values are not coerced to an object.
+  a = [];
+  [1, 2].some(function() { a.push(this) }, {});
+  assertFalse(a[0] !== a[1]);
+
+  // In strict mode, when evaluating 'this', primitive values should not be
+  // coerced to an object.
+  a = [];
+  [1, 2].some(function() { 'use strict'; a.push(this); }, "");
+  assertTrue(a[0] === "" && a[0] === a[1]);
+
 })();