test262/test/language/expressions/object/computed-__proto__.js

// Copyright (C) 2017 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: prod-PropertyDefinition
description: >
  computed __proto__ property key is assigned to an own property
info: |
  12.2.6 Object Initializer

  PropertyDefinition[Yield, Await] :
    PropertyName[?Yield, ?Await] : AssignmentExpression[+In, ?Yield, ?Await]

  PropertyName[Yield, Await] :
    LiteralPropertyName
    ComputedPropertyName[?Yield, ?Await]

  ComputedPropertyName[Yield, Await] :
    [ AssignmentExpression[+In, ?Yield, ?Await] ]

  B.3.1__proto__ Property Names in Object Initializers

  ...
  5. If propKey is the String value "__proto__" and if IsComputedPropertyKey(propKey)
    is false, then
    a. If Type(propValue) is either Object or Null, then
        i. Return object.[[SetPrototypeOf]](propValue).
    b. Return NormalCompletion(empty).
features: [Symbol]
---*/

var obj;
var sample = {};

obj = {
  ['__proto__']: sample
};
assert.sameValue(
  Object.getPrototypeOf(obj),
  Object.prototype,
  'does not change the object prototype (ordinary object)'
);
assert(
  obj.hasOwnProperty('__proto__'),
  'computed __proto__ property is set as an own property (ordinary object)'
);
assert.sameValue(
  obj.__proto__,
  sample,
  'value is properly defined (ordinary object)'
);

obj = {
  ['__proto__']: null
};
assert.sameValue(
  Object.getPrototypeOf(obj),
  Object.prototype,
  'does not change the object prototype (null)'
);
assert(
  obj.hasOwnProperty('__proto__'),
  'computed __proto__ property is set as an own property (null)'
);
assert.sameValue(
  obj.__proto__,
  null,
  'value is properly defined (null)'
);

obj = {
  ['__proto__']: undefined
};
assert.sameValue(
  Object.getPrototypeOf(obj),
  Object.prototype,
  'does not change the object prototype (undefined)'
);
assert(
  obj.hasOwnProperty('__proto__'),
  'computed __proto__ property is set as an own property (undefined)'
);
assert.sameValue(
  obj.__proto__,
  undefined,
  'value is properly defined (undefined)'
);

var func = function() {};
obj = {
  ['__proto__']: func
};
assert.sameValue(
  Object.getPrototypeOf(obj),
  Object.prototype,
  'does not change the object prototype (func)'
);
assert(
  obj.hasOwnProperty('__proto__'),
  'computed __proto__ property is set as an own property (func)'
);
assert.sameValue(
  obj.__proto__,
  func,
  'value is properly defined (func)'
);

var symbol = Symbol('Leo');
obj = {
  ['__proto__']: symbol
};
assert.sameValue(
  Object.getPrototypeOf(obj),
  Object.prototype,
  'does not change the object prototype (symbol)'
);
assert(
  obj.hasOwnProperty('__proto__'),
  'computed __proto__ property is set as an own property (symbol)'
);
assert.sameValue(
  obj.__proto__,
  symbol,
  'value is properly defined (symbol)'
);

obj = {
  ['__proto__']: 42
};
assert.sameValue(
  Object.getPrototypeOf(obj),
  Object.prototype,
  'does not change the object prototype (number)'
);
assert(
  obj.hasOwnProperty('__proto__'),
  'computed __proto__ property is set as an own property (number)'
);
assert.sameValue(
  obj.__proto__,
  42,
  'value is properly defined (number)'
);

obj = {
  ['__proto__']: ''
};
assert.sameValue(
  Object.getPrototypeOf(obj),
  Object.prototype,
  'does not change the object prototype (string)'
);
assert(
  obj.hasOwnProperty('__proto__'),
  'computed __proto__ property is set as an own property (string)'
);
assert.sameValue(
  obj.__proto__,
  '',
  'value is properly defined (string)'
);

obj = {
  ['__proto__']: false
};
assert.sameValue(
  Object.getPrototypeOf(obj),
  Object.prototype,
  'does not change the object prototype (boolean)'
);
assert(
  obj.hasOwnProperty('__proto__'),
  'computed __proto__ property is set as an own property (boolean)'
);
assert.sameValue(
  obj.__proto__,
  false,
  'value is properly defined (boolean)'
);