Version

3.0.0-rc.10

Node and OS info

Node 10.6.0 / Yarn 1.9.2 / macOS 10.13.5

Steps to reproduce

1. Clone https://github.com/mserajnik/vue-cli-promise-finally
2. Install with Yarn
3. Run with yarn serve
4. Open the development URL in Firefox (tested under Firefox 61.0.1)
5. Check the console: [Vue warn]: Error in created hook: "TypeError: this.fetchData(...).then(...).catch(...).finally is not a function"

What is expected?

According to the MDN web docs, Promise.prototype.finally() is supported natively in Firefox since 58, so it should work, even without any polyfill.

What is actually happening?

Promise.prototype.finally() does not work in Firefox (61.0.1).

Not sure if I'm missing something obvious here – I'm not even sure if this is actually a bug or just a configuration issue (maybe I have to adjust my babel.config.js in some way?). What is weird is that Promise.prototype.finally() works in Safari when I run the same test app, which doesn't have native support for it apparently – so the polyfill seems to be working there. I can only reproduce the issue in Firefox. A friend has also confirmed the same issue in Firefox under Windows 10.

Oh, and sorry if this issue belongs somewhere else. Since I couldn't pin down if it's a Firefox bug, an issue with Babel or one with the @vue/app preset (or just a configuration error on my end), it made the most sense to me to open it here first.