member-expression-async-identifier.js

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// |reftest| async

// Copyright 2019 Google, Inc.  All rights reserved.

// This code is governed by the BSD license found in the LICENSE file.

/*---

esid: prod-OptionalExpression

description: >

  optional chain on member expression in async context

info: |

  Left-Hand-Side Expressions

    OptionalExpression

      MemberExpression [PrimaryExpression identifier] OptionalChain

features: [optional-chaining]

flags: [async]

includes: [asyncHelpers.js]

---*/

const a = undefined;

const c = {d: Promise.resolve(11)};

async function checkAssertions() {

  assert.sameValue(await a?.b, undefined);

  assert.sameValue(await c?.d, 11);

  Promise.prototype.x = 42;

  var res = await Promise.resolve(undefined)?.x;

  assert.sameValue(res, 42, 'await unwraps the evaluation of the whole optional chaining expression #1');

  Promise.prototype.y = 43;

  var res = await Promise.reject(undefined)?.y;

  assert.sameValue(res, 43, 'await unwraps the evaluation of the whole optional chaining expression #2');

  c.e = Promise.resolve(39);

  assert.sameValue(await c?.e, 39, 'await unwraps the promise given after the evaluation of the OCE');

asyncTest(checkAssertions);