ERROR in only one instance of babel-polyfill is allowed @ ./~/bootstrap-loader/loader.js 1:0-44

[AllenFang]

I upgrade bootstrap-loader according #13, and it work for node@0.12.0 and earlier, but I got another problem for babel-polyfill is loaded repeatedly.

the error message is in the following:

ERROR in only one instance of babel-polyfill is allowed  @ ./~/bootstrap-loader/loader.js 1:0-44

The root cause is I wrote my dev webpack config with es6, and I add require('babel/register'); this line in my webpack-dev-server.js

Anyway, if re-write whole webpack config with es5 and it's work, so have any idea to solve it or did I miss something?

Thanks :)

[strawbrary]

I was about to create an issue for this but you beat me to it :) Are you using Babel 5 in your project? bootstrap-loader v1.0.3 includes the Babel 6 polyfill which will throw that error if your project is also pulling in the Babel 5 polyfill. You could try installing v1.0.1 of bootstrap-loader for now and see if that resolves it.

[AllenFang]

yep, I'm trying to upgrade to babel 6, but there some troubles I need to solve ;( But to the user of babel 5, your solutions seems like a workaround for now

[strawbrary]

I'm in the same boat, still on Babel 5, which is why I was going to create an issue to see if they intended to support projects which haven't upgraded yet.

[AllenFang]

👍

[alex35mil]

@AllenFang @strawbrary
Hey guys, somehow I wasn't subscribed to this repo and missed issue, sorry. I'll take a look at this tomorrow. Guess I can check what version of babel is installed and require it.

[alex35mil]

Also I'll check node version so babel-polyfill will be required only for node@<=0.12 users.

[AllenFang]

@alexfedoseev, it's a bad news for this repo and thanks your helping. Anyway, is there any basic docs or getting started for contributing this repo, I thinks maybe I can do some bug fixing or something like that.

[justin808]

@AllenFang I invited you to our slack room! Thanks so much for offering help!

[alex35mil]

@AllenFang I added Contributing guide with short explanations how things work. Let me know if you want to hack on this issue.

My current plan is:

/* ./src/bootstrap.loader.js */

if (semver.lte(process.version, '0.12.x')) {
  const babelLatest = 'babel-polyfill';
  const babelPrev = 'babel/polyfill';

  const isBabelLatest = require.resolve(babelLatest);
  const isBabelPrev = require.resolve(babelPrev);

  if (!isBabelLatest && !isBabelPrev) {
    throw ...
  }

  if (isBabelLatest) {
    require(babelLatest);
  } else {
    require(babelPrev);
  }
}

// imports ...

[AllenFang]

Thanks your helping, I'll spend some time to study and try my best to contribute this repo

[alex35mil]

Thanks, @AllenFang!

[alex35mil]

@AllenFang any updates on this? If you're currently busy, I can handle this issue.

[AllenFang]

um.. little busy, i think you can patch this issue if you have free times. sorry

[alex35mil]

@AllenFang Sure 👍

[genaro-picazo]

I am also having this issue when trying to use both bootstrap-loader and awesome-typescript-loader.