rollup + rollup-plugin-babel + @babel/polyfill

[robinloeffel]

When trying to build my project with rollup@latest, rollup-plugin-babel@latest, @babel/core@latest and @babel/polyfill@latest, I get the following error originating from rollup-plugin-babel:

[!] (babel plugin) TypeError: Cannot read property 'code' of null
node_modules/core-js/modules/es7.symbol.async-iterator.js
TypeError: Cannot read property 'code' of null
at /Users/robin.loeffel/Sites/misc/mehrsprachig/node_modules/rollup-plugin-babel/dist/rollup-plugin-babel.cjs.js:53:52
at Object.transform$1 (/Users/robin.loeffel/Sites/misc/mehrsprachig/node_modules/rollup-plugin-babel/dist/rollup-plugin-babel.cjs.js:174:18)
at /Users/robin.loeffel/Sites/misc/mehrsprachig/node_modules/rollup/dist/rollup.js:20831:25
at

You can check out my code here—I wouldn't be surprised if it's my fault. I'm not that experienced with rollup. 😄

It also sometimes appears with node_modules/regenerator-runtime/runtime.js instead of node_modules/core-js/modules/es7.symbol.async-iterator.js.

[Andarist]

Thanks for the report. It's a problem in the plugin - gonna fix it tomorrow.

[Andarist]

Could u try rollup-plugin-babel@beta?

[robinloeffel]

I works now, thank you! But I get the warning that "Plugins that transform code (such as 'babel') should generate accompanying sourcemaps", even though I have babel configured to output source maps.

module.exports = {
    sourceMaps: true,
    presets: [
        ['@babel/preset-env', {
            targets: {
                ie: 11,
                browsers: 'last 2 versions'
            },
            useBuiltIns: 'usage'
        }]
    ],
    ignore: [ 'node_modules' ]
};

import babel from 'rollup-plugin-babel';
import resolve from 'rollup-plugin-node-resolve';
import commonjs from 'rollup-plugin-commonjs';
import { uglify } from 'rollup-plugin-uglify';
import { eslint } from 'rollup-plugin-eslint';

// two separate objects for two separate outputs
// firstly esnext for bundlers, then umd for browsers
export default [{
    input: 'src/mehrsprachig.js',
    plugins: [
        eslint(),
        resolve(),
        commonjs()
    ],
    output: {
        dir: 'dist',
        sourcemap: true,
        file: 'mehrsprachig.es.js',
        format: 'es'
    }
}, {
    input: 'src/mehrsprachig.js',
    plugins: [
        eslint(),
        resolve(),
        commonjs(),
        babel(),
        uglify()
    ],
    output: {
        dir: 'dist',
        sourcemap: true,
        name: 'Mehrsprachig',
        file: 'mehrsprachig.umd.js',
        format: 'umd'
    }
}];

[Andarist]

Thanks for reporting back, I think we might need to return null instead of { code } when no transformation takes place (because of your ignore rule in babelrc). I need to investigate if it's supported in all current supported versions of rollup.

[Andarist]

I think this was fixed by some of the latest releases, closing this but I would appreciate you checking again if it works now correctly for you and reporting back if it does.

[robinloeffel]

Works correctly now, thanks!