[Bug Report] vue-cli-plugin breaks babel

[lol2x]

Versions and Environment

Vuetify: 1.3.3
Vue: 2.5.17
Browsers: Chrome 70.0.3538.77
OS: Windows 10

Steps to reproduce

Build project in modern mode

Expected Behavior

Legacy mode should be transpilled corectlly

Actual Behavior

Legacy file is not transpilled with babel

Reproduction Link

https://github.com/lol2x/TestModernLegacy

[KaelWD]

transpileDependencies: ['vuetify'] needs to be added to vue.config.js

[lol2x]

I believe this does not solve whole problem, for example after build check app-legacy.js it still has const store - which without vue-cli-plugin is transpilled to var.

[KaelWD]

https://caniuse.com/#feat=const

Legacy mode doesn't mean vuetify will magically start supporting IE10. Does the legacy build still work in IE11 with that change and --modern?

[lol2x]

Nope

[lol2x]

Also what i mean about const is - if you will try my repo without vue-cli-plugin added (init commit) it transpiles const to var.

[lol2x]

I believe index.js lines 11-15 is the issue.

[albertlinga]

@KaelWD

I modified vue.config.js to look like this

module.exports = {
transpileDependencies: ['vuetify']
}

But I'm getting errors now

Error: webpack-internal:///./node_modules/core-js/modules/_is-object.js:5
module.exports = function (it) {
^
TypeError: Cannot assign to read only property 'exports' of object '#'

[albertlinga]

#58 approach of removing include in js rule fixed it for me but I didn't transpile my dependency. transpiliing dependency caused the issue above regarding mixing import and module.exports

[breadadams]

After spending a day investigating why half of my app had suddenly stopped transpiling correctly upon build I've managed to pinpoint the issue to a recent migration from vue-cli 2 → 3, and with so the use of the vuetify CLI plugin in favor of a "manual" setup (so to say).

The main issue was that spread operators were being left in-tact, and therefore causing SCRIPT1028 errors in Edge/IE11, and missing : after property id in older versions of Firefox.

It would seem the issue lies within vuetify-loader (added during vue add vuetify from the a-la-carte option). After removing the dependency everything's back to normal, although of course the bundle size is a few kb larger now.

Is that what #58 intends to resolve @albertlinga @aeby ? 🤔

[albertlinga]

@breadadams yes #58 intends to solve your issue, however on my case transpileDependency caused more issues than fix. Removing the include in js rule as specified in #58 did the trick for me.

The missing : error you're getting is around the shorthand syntax e.g. data () if you look at app.vue and helloworld.vue from a demo app.