seal-and-freeze.js

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"use strict";

// Seal

assertEq(Object.isSealed(new Int32Array(2)), false);

assertEq(Object.isSealed(new Int32Array(0)), false);

var array = new Int32Array(0);

Object.preventExtensions(array);

assertEq(Object.isSealed(array), true);

// Non-empty typed arrays can never be sealed, because the elements stay configurable.

array = new Int32Array(1);

array.b = "test";

Object.preventExtensions(array);

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

Object.defineProperty(array, "b", {configurable: false});

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

array = new Int32Array(2);

array.b = "test";

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

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

assertThrowsInstanceOf(() => array.c = 15, TypeError);

// Freeze

assertEq(Object.isFrozen(new Int32Array(2)), false);

assertEq(Object.isFrozen(new Int32Array(0)), false);

// Empty non-extensible typed-array is trivially frozen

var array = new Int32Array(0);

Object.preventExtensions(array);

assertEq(Object.isFrozen(array), true);

array = new Int32Array(0);

array.b = "test";

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

Object.preventExtensions(array);

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

Object.defineProperty(array, "b", {configurable: false, writable: false});

assertEq(Object.isFrozen(array), true);

// Non-empty typed arrays can never be frozen, because the elements stay writable

array = new Int32Array(1);

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

assertEq(Object.isExtensible(array), false);

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

if (typeof reportCompare === "function")

    reportCompare(true, true);