custom-proto-access-resizes-buffer-valid-by-offset.js (1258B)
1 // Copyright (C) 2021 the V8 project authors. All rights reserved. 2 // This code is governed by the BSD license found in the LICENSE file. 3 /*--- 4 esid: sec-dataview-buffer-byteoffset-bytelength 5 description: > 6 The view's offset may equal the underlying buffer's byte length if it is 7 modified during retrieval of the NewTarget's prototype. 8 features: [resizable-arraybuffer] 9 ---*/ 10 11 // If the host chooses to throw as allowed by the specification, the observed 12 // behavior will be identical to the case where `ArrayBuffer.prototype.resize` 13 // has not been implemented. The following assertion prevents this test from 14 // passing in runtimes which have not implemented the method. 15 assert.sameValue(typeof ArrayBuffer.prototype.resize, 'function'); 16 17 var buffer = new ArrayBuffer(3, {maxByteLength: 3}); 18 var expectedByteLength; 19 20 var newTarget = function() {}.bind(null); 21 Object.defineProperty(newTarget, 'prototype', { 22 get: function() { 23 try { 24 buffer.resize(2); 25 expectedByteLength = 0; 26 } catch (error) { 27 expectedByteLength = 1; 28 } 29 } 30 }); 31 32 var result = Reflect.construct(DataView, [buffer, 2], newTarget); 33 34 assert.sameValue(result.constructor, DataView); 35 assert.sameValue(result.byteLength, expectedByteLength); 36 37 reportCompare(0, 0);