length-truncate-nonconfigurable.js

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/*

 * Any copyright is dedicated to the Public Domain.

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

 * Contributor:

 *   Jeff Walden <jwalden+code@mit.edu>

*/

//-----------------------------------------------------------------------------

var BUGNUMBER = 858381;

var summary =

  "Array length redefinition behavior with non-configurable elements";

print(BUGNUMBER + ": " + summary);

/**************

 * BEGIN TEST *

 **************/

var arr = [0, 1, 2];

Object.defineProperty(arr, 1, { configurable: false });

try

  Object.defineProperty(arr, "length", { value: 0, writable: false });

catch (e)

  assertEq(e instanceof TypeError, true,

           "must throw TypeError when array truncation would have to remove " +

           "non-configurable elements");

assertEq(arr.length, 2, "length is highest remaining index plus one");

var desc = Object.getOwnPropertyDescriptor(arr, "length");

assertEq(desc !== undefined, true);

assertEq(desc.value, 2);

assertEq(desc.writable, false);

assertEq(desc.enumerable, false);

assertEq(desc.configurable, false);

/******************************************************************************/

if (typeof reportCompare === "function")

  reportCompare(true, true);

print("Tests complete");