ESLint errors for code injected by Babel

I’m using Babel with preset-env for IE support (sad, I know), and I’m getting these errors:

/.../TestWorker.js
  4:3   warning  Unexpected var, use let or const instead  no-var
  5:29  warning  Unexpected function expression            prefer-arrow-callback
  8:7   warning  Expected property shorthand               object-shorthand
 10:12  warning  Unexpected function expression            prefer-arrow-callback
 13:7   warning  Expected property shorthand               object-shorthand

The warnings seem to be about code that would be injected by Babel, but ESLint runs with enforce: pre, so looks like double processing. This happens only for the worker the rest of the code is built correctly.

Here’s the (simplified) code for my worker:

import process from './process';

self.onmessage = ({data}) =>
	process(data)
		.then(result => postMessage({type: 'success', result}))
		.catch(error => postMessage({type: 'error', error}));

This could be related to the problem reported in #86.

[jcestibariz]

@dohun-toss I had not noticed that eslint-loader was deprecated. Using eslint-webpack-plugin fixed the problem, thank you!

[dohun-toss]

module.exports = {
  // ...
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: ['babel-loader', 'eslint-loader'], // without enforce pre, you can use lint first
      },
    ],
  },
  // ...
};

but, eslint-loader is deprecated. how about trying to migrate to eslint-webpack-plugin?

Before:

module.exports = {
  // ...
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        loader: 'eslint-loader',
        options: {
          // eslint options (if necessary)
        },
      },
    ],
  },
  // ...
};

After:

const ESLintPlugin = require('eslint-webpack-plugin');

module.exports = {
  // ...
  plugins: [new ESLintPlugin(options)],
  // ...
};