Uncompiled ES6

[gagarin55]

I'm using create-react-app tool, when I try to use web3-privider-engine I receive errors during the build.
I've described issue there facebook/create-react-app#1907

The problem is that you provide some uncompiled ES6 modules. Could you give me please some advice how to resolve it.

[gagarin55]

After this https://github.com/MetaMask/provider-engine/blob/master/package.json#L18 I even can't run it ;( Why you don't provide compiled npm packages ? ;(

[Moejoe90]

I am facing exactly the same issue, have you managed to fix this?
I have managed to do a temporary fix, if you go down to version 11.0.0 from 12.0.0 the create-react-app tool will work

[danfinlay]

Possible solutions to this:

1. We remove ES7 from eth-block-tracker
2. We declare we are now strictly ES7, and you need to transpile your project using something like babel.
3. Eth-block-tracker could include transpiling in its build process, and we export that instead.

Looks like we're going to start looking at a better pattern for transpiling eth-block-tracker, and making this reverse-compatible again.

[danfinlay]

We're going to track this in MetaMask too:
MetaMask/metamask-extension#1337

[danfinlay]

Fixed in web3-provider-engine@12.0.2. @Moejoe90 @gagarin55 @LogvinovLeon

[Moejoe90]

Thanks for the fix, everything is working fine now

[moodysalem]

This happens with react-scripts 1.0.14 and web3-provider-engine 13.3.3 when I try to import the ZeroClientProvider

Failed to minify the code from this file: 

        ./node_modules/web3-provider-engine/dist/ZeroClientProvider.js:30 

Read more here: http://bit.ly/2tRViJ9

This is line 30 of that file

  self._blockTracker.on('block', (jsonBlock) => {

My guess is the arrow function is detected as ES6, and the support of arrow functions is still not great (78%)

I'm just using a rawgit script tag for now and accessing window.ZeroClientProvider

    <script src="https://cdn.rawgit.com/MetaMask/provider-engine/f39dabd9/dist/ZeroClientProvider.js"
            integrity="sha384-1bhcGKfQdEyjqsWD7rhaxbxPKxU8nPn7hZ4wsgGTpMZdKVC8aTLblsgmE3P0g2Tm"
            crossorigin="anonymous"></script>

Actually this may be a newly introduced issue now that I read into the original issue more