Webpacker, babel, uglifyjs-webpack-plugin - not transforming arrow functions, but only in Vue files - ruby-on-rails

Question

Running webpacker 3.5.5 (both the gem and package). This is mostly working, but in IE11 the app is broken because arrow functions do not appear to be transformed. However, inspecting the minified code it seems like the only place arrow functions aren't transformed are inside my vue components.
I think this is because my babel class properties plugin is not applying to my Vue loader somehow, but I haven't been able to come up with a solution.
Here's my .babelrc
{
"presets": [
[
"env",
{
"modules": false,
"targets": {
"browsers": [
"> 1%",
"IE 11"
],
"uglify": true
},
"useBuiltIns": true
}
]
],
"plugins": [
"syntax-dynamic-import",
"transform-object-rest-spread",
[
"transform-class-properties",
{
"spec": true
}
]
],
"env": {
"test": {
"presets": ["es2015"]
}
}
}
And here's the entirety of my environment.js file that modifies the webpack environment that webpacker ships with (vue loader is at the bottom).
const { environment } = require('#rails/webpacker');
environment.loaders.append('expose', {
test: require.resolve('jquery'),
use: [{
loader: 'expose-loader',
options: 'jQuery'
}]
});
const webpack = require('webpack');
// append some global plugins
environment.plugins.append('Provide', new webpack.ProvidePlugin({
$: 'jquery',
jQuery: 'jquery',
axios: 'axios',
moment: 'moment-timezone',
_: 'lodash'
}));
// Necesary configuration for vue-loader v15
const VueLoaderPlugin = require('vue-loader/lib/plugin');
environment.plugins.append(
'VueLoaderPlugin',
new VueLoaderPlugin()
);
environment.loaders.append('vue', {
test: /\.vue$/,
loader: 'vue-loader'
});
module.exports = environment;
Edit for more info: Here is the entry point to my pack called 'wrestling'
import 'babel-polyfill';
import 'wrestling';
Then in wrestling.js...
import './styles/wrestling'
import Rails from 'rails-ujs'
Rails.start();
import wrestlingSetup from './wrestlingSetup'
wrestlingSetup();
WrestlingSetup contains the actual references to the vue files. I've cut down the file to show what a single vue import looks like within the file. All the rest are essentially the same.
import Vue from 'vue/dist/vue.esm'
// Redacted a bunch of imports, but they all look like this oen
import WrestlerCreate from './vue/wrestler_create.vue'
export default function() {
document.addEventListener('DOMContentLoaded', () => {
axiosSetup();
const app = new Vue({
el: '#app',
components: {
// Other vue components here that I've removed for simplicity
WrestlerCreate,
}
})
});
}
Here's an actual example of the Vue component
<template>
<div role="form">
<!-- other form elements -->
</div>
</template>
<script>
export default {
name: 'wrestler-create',
props: [
],
// This does not get transformed by babel
data() {
return {
loading: false,
error: false,
errorMessage: "Error, please try again later or contact support.",
first_name: '',
last_name: '',
weight_class: '',
academic_class: ''
}
},
methods: {
// removed for simplicity
}
}
</script>

Answer 1

For clarify sake:
Please use function() for data. I find function() gives me less trouble than arrow functions.
export default {
data: function() {
return {
message: "Hello something!",
secondMessage: "Hello world!"
};
}
}
If you really wish to use arrow function, you can write:
export default {
data: () => {
return {
message: "Hello something!",
secondMessage: "Hello world!"
};
}
}