nativeElementAccesses.js

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function testOverwritingSparseHole()

  var x = [];

  for (var i = 0; i < 50; i++)

    x[i] = i;

  var hit = false;

  Object.defineProperty(x, 40, {set: function() { hit = true; }});

  for (var i = 0; i < 50; i++)

    x[i] = 10;

  assertEq(hit, true);

testOverwritingSparseHole();

function testReadingSparseHole()

  var x = [];

  for (var i = 5; i < 50; i++)

    x[i] = i;

  var hit = false;

  Object.defineProperty(x, 40, {get: function() { hit = true; return 5.5; }});

  var res = 0;

  for (var i = 0; i < 50; i++) {

    res += x[i];

    if (i == 10)

      res = 0;

  assertEq(res, 1135.5);

  assertEq(hit, true);

testReadingSparseHole();

function testInSparseHole()

  var x = [];

  for (var i = 5; i < 50; i++)

    x[i] = i;

  Object.defineProperty(x, 40, {get: function() {}});

  var res = 0;

  for (var i = 0; i < 50; i++)

    res += (i in x) ? 1 : 0;

  assertEq(res, 45);

testInSparseHole();