bug2012018-3.js - mozsearch

Enable keyboard shortcuts

// Test various property suppression edge cases for for-in enumeration. Note that

// some of this is implementation-defined, but if our behavior changes we want to

// know about it.

function testBasic() {

  var proto = {y: 1};

  var obj = Object.create(proto);

  Object.assign(obj, {x: 2, y: 3});

  var log = "";

  for (var p in obj) {

    log += p;

    delete obj.y;

  // proto.y took the place of obj.y.

  assertEq(log, "xy");

testBasic();

function testNonEnumerable() {

  var proto = {};

  Object.defineProperty(proto, "y", {value: 1, enumerable: false, writable: true});

  var obj = Object.create(proto);

  Object.assign(obj, {x: 2, y: 3});

  var log = "";

  for (var p in obj) {

    log += p;

    delete obj.y;

  // proto.y is non-enumerable so "y" is suppressed.

  assertEq(log, "x");

testNonEnumerable();

function testDense() {

  var proto = {};

  proto[0] = 1;

  proto[1] = 2;

  var obj = Object.create(proto);

  Object.assign(obj, {0: 1, 1: 2});

  var log = "";

  for (var p in obj) {

    log += p;

    delete obj[1];

  // proto[0] took the place of obj[0].

  assertEq(log, "01");

testDense();

function testIndexNonEnumerable() {

  var proto = {};

  proto[0] = 1;

  Object.defineProperty(proto, 1, {value: 2, enumerable: false, writable: true});

  var obj = Object.create(proto);

  Object.assign(obj, {0: 1, 1: 2});

  var log = "";

  for (var p in obj) {

    log += p;

    delete obj[1];

  // proto[1] is non-enumerable so "1" is suppressed.

  assertEq(log, "0");

testIndexNonEnumerable();