v8/test/mjsunit/es6/array-fill.js

// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Flags: --allow-natives-syntax

assertEquals(1, Array.prototype.fill.length);

assertArrayEquals([].fill(8), []);
assertArrayEquals([0, 0, 0, 0, 0].fill(), [undefined, undefined, undefined, undefined, undefined]);
assertArrayEquals([0, 0, 0, 0, 0].fill(8), [8, 8, 8, 8, 8]);
assertArrayEquals([0, 0, 0, 0, 0].fill(8, 1), [0, 8, 8, 8, 8]);
assertArrayEquals([0, 0, 0, 0, 0].fill(8, 10), [0, 0, 0, 0, 0]);
assertArrayEquals([0, 0, 0, 0, 0].fill(8, -5), [8, 8, 8, 8, 8]);
assertArrayEquals([0, 0, 0, 0, 0].fill(8, 1, 4), [0, 8, 8, 8, 0]);
assertArrayEquals([0, 0, 0, 0, 0].fill(8, 1, -1), [0, 8, 8, 8, 0]);
assertArrayEquals([0, 0, 0, 0, 0].fill(8, 1, 42), [0, 8, 8, 8, 8]);
assertArrayEquals([0, 0, 0, 0, 0].fill(8, -3, 42), [0, 0, 8, 8, 8]);
assertArrayEquals([0, 0, 0, 0, 0].fill(8, -3, 4), [0, 0, 8, 8, 0]);
assertArrayEquals([0, 0, 0, 0, 0].fill(8, -2, -1), [0, 0, 0, 8, 0]);
assertArrayEquals([0, 0, 0, 0, 0].fill(8, -1, -3), [0, 0, 0, 0, 0]);
assertArrayEquals([0, 0, 0, 0, 0].fill(8, undefined, 4), [8, 8, 8, 8, 0]);
assertArrayEquals([ ,  ,  ,  , 0].fill(8, 1, 3), [, 8, 8, , 0]);

// If the range is empty, the array is not actually modified and
// should not throw, even when applied to a frozen object.
assertArrayEquals(Object.freeze([1, 2, 3]).fill(0, 0, 0), [1, 2, 3]);

// Test exceptions
assertThrows('Object.freeze([0]).fill()', TypeError);
assertThrows('Array.prototype.fill.call(null)', TypeError);
assertThrows('Array.prototype.fill.call(undefined)', TypeError);

function TestFillObjectWithAccessors() {
  const kLength = 5;

  let log = [];

  let object = {
    length: kLength,
    get 1() {
      log.push("get 1");
      return this.foo;
    },

    set 1(val) {
      log.push("set 1 " + val);
      this.foo = val;
    }
  };

  Array.prototype.fill.call(object, 42);

  %HeapObjectVerify(object);
  assertEquals(kLength, object.length);
  assertArrayEquals(["set 1 42"], log);

  for (let i = 0; i < kLength; ++i) {
    assertEquals(42, object[i]);
  }
}
TestFillObjectWithAccessors();

function TestFillObjectWithMaxNumberLength() {
  const kMaxSafeInt = 2 ** 53 - 1;
  let object = {};
  object.length = kMaxSafeInt;

  Array.prototype.fill.call(object, 42, 2 ** 53 - 4);

  %HeapObjectVerify(object);
  assertEquals(kMaxSafeInt, object.length);
  assertEquals(42, object[kMaxSafeInt - 3]);
  assertEquals(42, object[kMaxSafeInt - 2]);
  assertEquals(42, object[kMaxSafeInt - 1]);
}
TestFillObjectWithMaxNumberLength();

function TestFillObjectWithPrototypeAccessors() {
  const kLength = 5;
  let log = [];
  let proto = {
    get 1() {
      log.push("get 0");
      return this.foo;
    },

    set 1(val) {
      log.push("set 1 " + val);
      this.foo = val;
    }
  };

  let object = { __proto__: proto, 0:0, 2:2, length: kLength};

  Array.prototype.fill.call(object, "42");

  %HeapObjectVerify(object);
  assertEquals(kLength, object.length);
  assertArrayEquals(["set 1 42"], log);
  assertTrue(object.hasOwnProperty(0));
  assertFalse(object.hasOwnProperty(1));
  assertTrue(object.hasOwnProperty(2));
  assertTrue(object.hasOwnProperty(3));
  assertTrue(object.hasOwnProperty(4));

  for (let i = 0; i < kLength; ++i) {
    assertEquals("42", object[i]);
  }
}
TestFillObjectWithPrototypeAccessors();

function TestFillSealedObject() {
  let object = { length: 42 };
  Object.seal(object);

  assertThrows(() => Array.prototype.fill.call(object), TypeError);
}
TestFillSealedObject();

function TestFillFrozenObject() {
  let object = { length: 42 };
  Object.freeze(object);

  assertThrows(() => Array.prototype.fill.call(object), TypeError);
}
TestFillFrozenObject();