Why babelConfig not working in webpack encore? - vue.js

Question

I want to add support for async / await functions for my project.
I install
"#babel/core": "^7.2.0",
"#babel/plugin-transform-runtime": "^7.2.0",
"#babel/preset-env": "^7.2.0",
"#babel/preset-es2015": "^7.0.0-beta.53",
"#babel/preset-stage-2": "^7.0.0",
"#babel/runtime": "^7.2.0",
It's my webpack.config.js
const Encore = require('#symfony/webpack-encore');
Encore
.setOutputPath('public/build')
.setPublicPath('/build')
.addEntry('app', './assets/app.js')
.enableSourceMaps(!Encore.isProduction())
.cleanupOutputBeforeBuild()
.enableBuildNotifications()
.enableVueLoader()
.configureBabel(function(babelConfig) {
babelConfig.presets.push('#babel/preset-env');
babelConfig.presets.push('#babel/preset-stage-2');
babelConfig.plugins.push('#babel/plugin-transform-runtime');
})
;
const config = Encore.getWebpackConfig();
config.externals = {
mode: 'development',
// global app config object
config: JSON.stringify({
apiUrl: 'http://localhost:80',
devServer: {
public: 'http://localhost:3000',
disableHostCheck: true,
},
})
};
config.node = {
fs: "empty"
};
module.exports = config;
When I run a server dev, I get an error.
Module build failed (from ./node_modules/babel-loader/lib/index.js):
Error: Duplicate plugin/preset detected.
If you'd like to use two separate instances of a plugin,
they need separate names, e.g.
plugins: [
['some-plugin', {}],
['some-plugin', {}, 'some unique name'],
]
I can not understand what the problem is.
I also created a .babelrc file and wrote the same configuration in it. But unfortunately, this did not help (

Answer 1

Use .babelrc for change babel config like this. This file should be in your project root
{
"plugins": ["#babel/plugin-transform-runtime"],
"presets": [
[
"#babel/preset-env",
...
],
...
]
}
Then remove this from your webpack.config.js
.configureBabel(function(babelConfig) {
babelConfig.presets.push('#babel/preset-env');
babelConfig.presets.push('#babel/preset-stage-2');
babelConfig.plugins.push('#babel/plugin-transform-runtime');
})