tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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target-is-frozen-data-property-set-throws.js (1729B)

      1 // Copyright (C) 2021 Alexey Shvayka. All rights reserved.
      2 // This code is governed by the license found in the LICENSE file.
      3 
      4 /*---
      5 esid: sec-object.assign
      6 description: >
      7  [[Set]] to data property of frozen `target` fails with TypeError.
      8 info: |
      9  SetIntegrityLevel ( O, level )
     10 
     11  [...]
     12  3. Let status be ? O.[[PreventExtensions]]().
     13  [...]
     14  7. Else,
     15    a. Assert: level is frozen.
     16    b. For each element k of keys, do
     17      i. Let currentDesc be ? O.[[GetOwnProperty]](k).
     18      ii. If currentDesc is not undefined, then
     19        1. If IsAccessorDescriptor(currentDesc) is true, then
     20          [...]
     21        2. Else,
     22          a. Let desc be the PropertyDescriptor { [[Configurable]]: false, [[Writable]]: false }.
     23        3. Perform ? DefinePropertyOrThrow(O, k, desc).
     24  8. Return true.
     25 
     26  Object.assign ( target, ...sources )
     27 
     28  [...]
     29  3. For each element nextSource of sources, do
     30    a. If nextSource is neither undefined nor null, then
     31      [...]
     32      iii. For each element nextKey of keys, do
     33        1. Let desc be ? from.[[GetOwnProperty]](nextKey).
     34        2. If desc is not undefined and desc.[[Enumerable]] is true, then
     35          [...]
     36          b. Perform ? Set(to, nextKey, propValue, true).
     37 
     38  OrdinarySetWithOwnDescriptor ( O, P, V, Receiver, ownDesc )
     39 
     40  [...]
     41  3. If IsDataDescriptor(ownDesc) is true, then
     42    a. If ownDesc.[[Writable]] is false, return false.
     43 features: [Symbol, Reflect]
     44 ---*/
     45 
     46 var sym = Symbol();
     47 var target1 = { [sym]: 1 };
     48 
     49 Object.freeze(target1);
     50 assert.throws(TypeError, function() {
     51  Object.assign(target1, { [sym]: 1 });
     52 });
     53 
     54 
     55 var target2 = Object.freeze({ foo: 1 });
     56 
     57 assert.throws(TypeError, function() {
     58  Object.assign(target2, { foo: 1 });
     59 });
     60 
     61 reportCompare(0, 0);