Babel-loader looses correct error stack when Promise and react-router is used

[gryzzly]

When initial rendering kicks off in a Promise callback the error stack and location are lost. The stack and location are correct when using transform-loader?babelify with exact same code.

Here's babel-loader:

Here babelify via webpack’s transform-loader yields correct code location:

I've tried to compile the minimal code to reproduce, removing routing from the code solves the problem, but with babelify it works without removing routing: https://github.com/gryzzly/babel-loader-issue

[zloirock]

zloirock/core-js#107. Unhandled rejection tracking is not a part of spec. Stack - also. If you wanna help implement long stack trace - welcome.

[gryzzly]

@zloirock thanks for the reply! this doesn't only happen with core-js Promise, I tried bluebird as well, stack is lost only with babel-loader and again is not lost with transform?babelify

[zloirock]

You tried bluebird with Promise.longStackTraces()?

[gryzzly]

@zloirock I tried previously with less "reduced" setup (more of my app code was in the example).

Retried again and now I can see that actually bluebird will provide stack trace with longStackTraces() with both babel-loader and transform?babelify, but it will point at compiled bundle rather than original code via source map. In entry point file at the top:

import Promise from 'bluebird';
Promise.longStackTraces();
require('babel-runtime/core-js/promise').default = Promise;

I put that above other requires and I could definitely see that bluebird was picked up. The trace it prints is different as it’s using console.warn. So with bluebird I get this with both loaders:

[gryzzly]

I found that in my case just using window.Promise solves the issue as I need this to work only in Chrome. That proves the issue lies in es6.promise.js indeed as you suggested and so can be closed. Thanks for looking into it!

[benjamingr]

zloirock/core-js#107. Unhandled rejection tracking is not a part of spec. Stack - also. If you wanna help implement long stack trace - welcome.

Actually, it's a part of the spec - tc39/ecma262#76

[zloirock]

@benjamingr I mean ES6 :) Anyway, unhandled rejection tracking available.