Object.prototype.preventExtensions.html

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This WPT test may be referenced by the following Test IDs:
- /js/builtins/Object.prototype.preventExtensions.html - WPT Dashboard Interop Dashboard

<!doctype html>

<html>

<head>

<meta charset="utf-8">

<title>Object.preventExtensions</title>

<link rel="author" title="Masaya Iseki" href="mailto:iseki.m.aa@gmail.com">

<link rel="help" href="https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.preventextensions">

<script src=/resources/testharness.js></script>

<script src=/resources/testharnessreport.js></script>

<script>

test(function() {

  [{}, []].forEach(function(that){

    assert_true(Object.isExtensible(that));

    that.prop = 'exist';

    Object.preventExtensions(that);

    assert_false(Object.isExtensible(that));

    assert_false(Object.isFrozen(that));

    assert_false(Object.isSealed(that));

    that.extension = 'This property should not be added';

    assert_equals(undefined, that.extension, 'Confirm to prevent adding property.');

    that.prop = 'changed';

    assert_equals('changed', that.prop,

          'Confirm to be able to change a property value.');

    delete that.prop;

    assert_equals(undefined, that.prop, 'Confirm to be able to delete a property.');

});

});

</script>

</body>

</html>