Amazon-cognito-identity-js: Why some of the API not follow function(err, data) callback signature?

[missing1984]

Why some of the API such as globalSignOut,getDevice,forgetDevice require onSuccess and onFailure function in the callback? Can they just follow universal function(err, data) signature?

[missing1984]

especially, the globalSignOut function expect callback to be a function and also with onFailure, onSuccess function attached.

  globalSignOut(callback) {
    if (this.signInUserSession == null || !this.signInUserSession.isValid()) {
      return callback(new Error('User is not authenticated'), null);
    }

    this.client.makeUnauthenticatedRequest('globalSignOut', {
      AccessToken: this.signInUserSession.getAccessToken().getJwtToken(),
    }, err => {
      if (err) {
        return callback.onFailure(err);
      }
      this.clearCachedTokens();
      return callback.onSuccess('SUCCESS');
    });
    return undefined;
  }

[jbailey2010]

The design of the callbacks was done largely to keep consistency between this and Cognito's sync SDK. A change is under consideration, however, as you can see from #88

[missing1984]

@jbailey2010 I think it's 2 issues, one is to fix the mixed style callback function while #88 is for adding promise support.

[itrestian]

Thanks Michael, we are definitely considering making changes to the callback style. However, at this point, that would be a breaking change so it has to be planned and carried out carefully.

[missing1984]

@itrestian could it be possible to do a check for given callback, call it if it's a function while invoke onSuccess,onFailure if it's a object. Seems not going to break anything.

[simonbuchan]

That's the change I suggested in #88 (note that I am not an Amazon employee though), since to support promises in existing APIs without breaking back-compat it's simpler to do that than not.

It might be an earlier PR, but I want to get my tests branch up with decent coverage first.

[sbussard]

Is the callback argument ever called by itself?

If that's not the case, then a simple fix would be to rename callback to options because it's just an object with callback functions in it.

That would be more semantically correct

[itrestian]

Don't think callback is called on it's own. Closing this in favour of https://github.com/aws/amazon-cognito-identity-js/issues/238.

[kelvanince1]

@itrestian You are closing these issues way too early mate.