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<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.');
  });
});

test(function() {
  ['foo', 42, null, undefined].forEach(function(that) {
    assert_throws(new TypeError(),
        function() { Object.preventExtensions(that) });
  });
});
</script>

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