JSTests/stress/define-own-indexed-property-fast-path.js

function assertSameDescriptor(a, b) {
  const aString = JSON.stringify(a, null, 2);
  const bString = JSON.stringify(b, null, 2);

  if (aString !== bString)
    throw new Error(`Bad descriptor!\nActual: ${aString}\nExpected: ${bString}`);
}

function getCombinations(options) {
  const optionKeys = Object.keys(options);
  const results = [];

  function getNextCombination(optionIndex, current) {
    const optionKey = optionKeys[optionIndex];

    for (const value of options[optionKey]) {
      current[optionKey] = value;

      const nextIndex = optionIndex + 1;
      if (nextIndex < optionKeys.length) {
        getNextCombination(nextIndex, current);
        break;
      }

      // deep clone `current` and remove `undefined` values
      const result = JSON.parse(JSON.stringify(current));
      results.push(result);
    }
  }

  getNextCombination(0, {});
  return results;
}

function testCreateProperty(object, key, descriptor) {
  if (object.hasOwnProperty(key))
    throw new Error(`Property ${key} should not exist.`);

  Object.defineProperty(object, key, descriptor);

  assertSameDescriptor(
    Object.getOwnPropertyDescriptor(object, key),
    {value: undefined, writable: false, enumerable: false, configurable: false, ...descriptor},
  );
}

function testRedefineProperty(object, key, descriptor) {
  if (!object.hasOwnProperty(key))
    throw new Error(`Property ${key} should exist.`);

  const value = object[key];
  Object.defineProperty(object, key, descriptor);

  assertSameDescriptor(
    Object.getOwnPropertyDescriptor(object, key),
    {value, writable: true, enumerable: true, configurable: true, ...descriptor},
  );
}

const dataDescriptor = {
  value: [1, 2, undefined],
  writable: [true, false, undefined],
  enumerable: [true, false, undefined],
  configurable: [true, false, undefined],
};

const accessorDescriptor = {
  get: [function() {}, undefined],
  set: [function(value) {}, undefined],
  enumerable: [true, false, undefined],
  configurable: [true, false, undefined],
};

for (const descriptor of getCombinations(dataDescriptor)) {
  testCreateProperty([], "0", descriptor);
  testRedefineProperty([1], "0", descriptor);
}

for (const descriptor of getCombinations(accessorDescriptor)) {
  testCreateProperty([1, 2], "2", descriptor);
  testRedefineProperty([1, 2, 3], "2", descriptor);
}