Kata 76 - Promise Creation - doesn't wrok in TDDbin

[rr326]

I couldn't get the kata to resolve. So I checked out the original checkin (which should pass). Tests 2&3 don't work.

But pasting it into Chrome debugger, it works properly (as it should).

Test

  describe('extending a `Promise`', function() {
    it('is possible', function() {
      class MyPromise extends Promise {}
      const promise = new MyPromise(resolve => resolve());

      promise
        .then(() => done())
        .catch(e => done(new Error('Expected to resolve, but failed with: ' + e)));
    });
    it('must call `super()` in the constructor if it wants to inherit/specialize the behavior', function() {
      // WARNING: this example doesn't fulfill the Liskov principle
      class ResolvingPromise extends Promise {
        constructor() {
          super(resolve => resolve());
        }
      }

      return new ResolvingPromise();
    });
  });

Returns

extending a Promise
is possible ‣
TypeError: # is not a promise
at new MyPromise (eval at runSpecs (http://tddbin.com/mocha/spec-runner.js:95056:7), :28:81)
at eval (eval at runSpecs (http://tddbin.com/mocha/spec-runner.js:95056:7), :34:21)
at r (http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:9112)
at r.o.run (http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:9812)
at o.runTest (http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:13250)
at http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:13824
at r (http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:12787)
at http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:12763
at n (http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:12554)
at http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:12618
must call super() in the constructor if it wants to inherit/specialize the behavior ‣
TypeError: # is not a promise
at new ResolvingPromise (eval at runSpecs (http://tddbin.com/mocha/spec-runner.js:95056:7), :53:88)
at eval (eval at runSpecs (http://tddbin.com/mocha/spec-runner.js:95056:7), :61:14)
at r (http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:9112)
at r.o.run (http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:9812)
at o.runTest (http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:13250)
at http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:13824
at r (http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:12787)
at http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:12763
at n (http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:12554)
at http://cdnjs.cloudflare.com/ajax/libs/mocha/2.1.0/mocha.min.js:2:12618

In Chrome

done = (retval) => `done ${retval}`
(retval) => `done ${retval}`
      class MyPromise extends Promise {}
      const promise = new MyPromise(resolve => resolve());

      promise
        .then(() => done())
        .catch(e => done(new Error('Expected to resolve, but failed with: ' + e)));

Returns

Promise {[[PromiseStatus]]: "resolved", [[PromiseValue]]: "done undefined"}

[fourcolors]

Verified on my end.

[ragmha]

Same here

[mii9000]

For me it works on Chrome if Transpile to ES5 is turned off. Would like to know the reason though.

[sandbox992]

Have another problem:

describe('extending a Promise', function() {
it('using class X extends Promise{} is possible', function(done) {
class MyPromise extends Promise {}
const promise = new MyPromise(resolve => resolve());
promise
.then(() => done())
.catch(e => done(new Error('Expected to resolve, but failed with: ' + e)));
});
it('must call super() in the constructor if it wants to inherit/specialize the behavior', function() {
class ResolvingPromise extends Promise {
constructor() {
super()
}
}
return new ResolvingPromise(resolve => resolve());
});
});

Returns:
Method Promise.prototype.then called on incompatible receiver #
Method Promise.prototype.then called on incompatible receiver #
for first and second tasks relatively

Similar problem(not mine, just found):
https://stackoverflow.com/questions/40404028/working-through-es6-katas-extending-promises

[wolframkriesing]

I was struggling to understand this issue. I played around with the kata, but I dont know what is meant that it doesnt work. If there is still interest, I would be keen on learning what the problem was (or still is).