src/v8/test/mjsunit/es6/typedarray-construct-by-buffer-ordering.js

// Copyright 2017 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.

(function TestThrowBeforeLengthToPrimitive() {
  // From 22.2.4.5 TypedArray ( buffer [ , byteOffset [ , length ] ] ), check
  // that step 7:
  //    If offset modulo elementSize ≠ 0, throw a RangeError exception.
  // happens before step 11:
  //    Let newLength be ? ToIndex(length).
  var expected = ["offset.toPrimitive"];
  var actual = [];
  var offset = {};
  offset[Symbol.toPrimitive] = function() {
    actual.push("offset.toPrimitive");
    return 1;
  };

  var length = {};
  length[Symbol.toPrimitive] = function() {
    actual.push("length.toPrimitive");
    return 1;
  };

  var buffer = new ArrayBuffer(16);

  assertThrows(function() {
    new Uint32Array(buffer, offset, length)
  }, RangeError);
  assertEquals(expected, actual);
})();

(function TestConstructByBufferToPrimitiveOrdering() {
  var expected = ["offset.toPrimitive", "length.toPrimitive"];
  var actual = [];
  var offset = {};
  offset[Symbol.toPrimitive] = function() {
    actual.push("offset.toPrimitive");
    return 1;
  };

  var length = {};
  length[Symbol.toPrimitive] = function() {
    actual.push("length.toPrimitive");
    return 1;
  };

  var buffer = new ArrayBuffer(16);
  var arr = new Uint8Array(buffer, offset, length);

  assertEquals(expected, actual);
  assertEquals(1, arr.length);
})();

(function TestByteOffsetToIndexThrowsForNegative() {
  var buffer = new ArrayBuffer(16);
  assertThrows(function() {
    new Uint8Array(buffer, -1);
  }, RangeError);
})();

(function TestByArrayLikeObservableOrdering() {
  var expected = [
    'proxy.Symbol(Symbol.iterator)', 'proxy.length', 'proxy.0', 'proxy.1',
    'proxy.2'
  ];
  var actual = [];

  var a = [1, 2, 3];
  var proxy = new Proxy(a, {
    get: function(target, name) {
      actual.push("proxy." + name.toString());
      if (name === Symbol.iterator) return undefined;
      return target[name];
    }
  });
  var arr = new Uint8Array(proxy);

  assertEquals(a.length, arr.length);
  assertEquals(expected, actual);
})();