resolve-thenable.js

// Copyright (C) 2016 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
description: Resolving with a thenable object value
es6id: 25.4.4.5
info: >
    [...]
    6. Let resolveResult be Call(promiseCapability.[[Resolve]], undefined,
       «x»).
    [...]

    25.4.1.3.2 Promise Resolve Functions
    [...]
    8. Let then be Get(resolution, "then").
    9. If then is an abrupt completion, then
       [...]
    10. Let thenAction be then.[[value]].
    11. If IsCallable(thenAction) is false, then
        [...]
    12. Perform EnqueueJob ("PromiseJobs", PromiseResolveThenableJob,
        «promise, resolution, thenAction»)
flags: [async]
---*/

var value = {};
var thenable = {
  then: function(resolve) {
    resolve(value);
  }
};

Promise.resolve(thenable).then(function(val) {
    if (val !== value) {
      $DONE('The promise should be fulfilled with the provided value.');
      return;
    }

    $DONE();
  }, function() {
    $DONE('The promise should not be rejected.');
  });