router: Configuring a route with "redirect" property causes BlueBird warnings

I’m submitting a bug report

Library Version: 1.0.1

Please tell us about your environment:

Operating System: Windows 10
Browser: all
Language: all

Current behavior: specifying “redirect” property in a route configuration, causes BlueBird warnings about “Warning: a promise was rejected with a non-error: [object Object]”

This comes from the router method:

  function _buildNavigationPlan(instruction, forceLifecycleMinimum) {
    var prev = instruction.previousInstruction;
    var config = instruction.config;
    var plan = {};

    if ('redirect' in config) {
      var redirectLocation = _resolveUrl(config.redirect, getInstructionBaseUrl(instruction));
      if (instruction.queryString) {
        redirectLocation += '?' + instruction.queryString;
      }

      return Promise.reject(new Redirect(redirectLocation));
    }

I tired creating a gist given the link in the Issue Template, however i can’t replicate it in a Gist - i’m assuming the bluebird promises library isn’t included in gists?

Expected/desired behavior: Not to create a warning in the console everytime that specific route is redirected

What is the motivation / use case for changing the behavior? Less warnings in the console

I understand that this is a BlueBird “quirk”, however I’m posing the question as to whether Aurelia adjusts its use of BlueBird to stop these warnings? or if we need to go to BlueBird and propose a “don’t warn me when a promise is rejected with a non-error” flag?

About this issue

Original URL
State: open
Created 7 years ago
Reactions: 4
Comments: 23 (14 by maintainers)

Commits related to this issue

fix(redirect): do not use Promise.reject on redirect Closes #480 — committed to fkleuver/router by fkleuver 6 years ago
Fix error introduced in 487c33d50fa938c9e725180877f6510ecae89db5 (when trying to fix #480) This causes #480 to re-appear until a better handling for cancellations exists — committed to rluba/router by rluba 6 years ago
Merge pull request #603 from rluba/fix/substate_redirects Fix error introduced in 487c33d5 (when trying to fix #480) — committed to aurelia/router by davismj 6 years ago

Most upvoted comments

Updates on this? This has been bugging me for a while now.

Is there really nothing else we can do except disable all warnings?

+10

indfnzo on Jul 5, 2017

@ry8806 I agree - it’s not ideal. In our app we’re using environment variables to turn on warnings only for debugging.

Looking at the w3 specification Promise.reject should return an Error object:

The w3 specification for Promises recommends that reject return an instance of Error. https://www.w3.org/2001/tag/doc/promises-guide#reasons-should-be-errors

Promise rejection reasons should always be instances of the ECMAScript Error type, just like synchronously-thrown exceptions should always be instances of Error as well.

Bluebird’s docs explain why: https://github.com/petkaantonov/bluebird/blob/master/docs/docs/warning-explanations.md

Due to a historic mistake in JavaScript, the throw statement is allowed to be used with any value, not just errors, and Promises/A+ choosing to inherit this mistake, it is possible to reject a promise with a value that is not an error.

The only way to stop the console warnings is to change the code to return an Error or not use Promise.reject for redirection.

@EisenbergEffect - What are your thoughts?

+10

jagonalez on Apr 19, 2017

I get this is a low profile issue but could we get an official response on whether we should expect this to be handled or if the only workaround is to disable warning?

Kukks on Oct 16, 2017

Technically-shmecnically It works? don’t change it! (-: How’s that for an argument?

Alexander-Taran on Mar 25, 2018

If you don’t want these to show then you need to disable them in your bluebird config:

If you’re using Aurelia CLI you can change it within the main.js file.

Promise.config({
  warnings: false
});

jagonalez on Apr 19, 2017

The fix introduced in 487c33d50fa938c9e725180877f6510ecae89db5 causes a much more serious error when redirecting in a sub-router config: TypeError: Cannot read property 'childRouter' of undefined is thrown because determineWhatToLoad(…) tries to interpret the Redirect plan as a regular plan because the rejection needs to be handled in more places than just the one checked in 487c33d50fa938c9e725180877f6510ecae89db5.

rluba on Jun 5, 2018

Technically it’s an uncaught error, and that’s certainly not a good thing.

fkleuver on Mar 25, 2018

@Kukks for the record, the problem is just a warning being logged to the console?

I think a good, viable long term fix would be to allow resolving a redirect as well. I agree that while the reject notation half makes sense, it half doesn’t. PRs welcome if someone wants to take a stab at that.

davismj on Feb 6, 2018

@jagonalez I’m aware of this, thanks

This “silence all warnings” flag isn’t the solution, by disabling ALL warnings (for the issue mentioned above) I might be losing out on other warnings that it may be trying to warn me about

ry8806 on Apr 19, 2017