typed-array-sealed-frozen.js

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// Any copyright is dedicated to the Public Domain.

// http://creativecommons.org/licenses/publicdomain/

load(libdir + "asserts.js")

const constructors = [

  Int8Array,

  Uint8Array,

  Uint8ClampedArray,

  Int16Array,

  Uint16Array,

  Int32Array,

  Uint32Array,

  Float16Array,

  Float32Array,

  Float64Array

];

for (constructor of constructors) {

  print("testing non-empty " + constructor.name);

  let a = new constructor(10);

  assertEq(Object.isExtensible(a), true);

  assertEq(Object.isSealed(a), false);

  assertEq(Object.isFrozen(a), false);

  // Should complain that it can't change attributes of indexed typed array properties.

  assertThrowsInstanceOf(() => Object.seal(a), TypeError);

  // Should complain that it can't change attributes of indexed typed array properties.

  assertThrowsInstanceOf(() => Object.freeze(a), TypeError);

print();

for (constructor of constructors) {

  print("testing zero-length " + constructor.name);

  let a = new constructor(0);

  assertEq(Object.isExtensible(a), true);

  assertEq(Object.isSealed(a), false);

  assertEq(Object.isFrozen(a), false);

  // Should not throw.

  Object.seal(a);

  Object.freeze(a);

// isSealed and isFrozen should not try to build an array of all the

// property names of a typed array, since they're often especially large.

// This should not throw an allocation error.

let a = new Uint8Array(1 << 24);

Object.isSealed(a);

Object.isFrozen(a);

for (constructor of constructors) {

  print("testing extensibility " + constructor.name);

  let a = new constructor(10);

  // New named properties should show up on typed arrays.

  a.foo = "twelve";

  assertEq(a.foo, "twelve");

  // New indexed properties should not show up on typed arrays.

  a[20] = "twelve";

  assertEq(a[20], undefined);

  // Watch for especially large indexed properties.

  a[-10 >>> 0] = "twelve";

  assertEq(a[-10 >>> 0], undefined);

  // Watch for really large indexed properties too.

  a[Math.pow(2, 53)] = "twelve";

  assertEq(a[Math.pow(2, 53)], undefined);

  // Don't define old properties.

  Object.defineProperty(a, 5, {value: 3});

  assertEq(a[5], 3);

  // Don't define new properties.

  assertThrowsInstanceOf(() => Object.defineProperty(a, 20, {value: 3}), TypeError);

  assertEq(a[20], undefined);

  // Don't delete indexed properties.

  a[3] = 3;

  delete a[3];

  assertEq(a[3], 3);