vue-cli-plugin-i18n | Vue CLI plugin to add vue

I don't think so you can achieve that, unless you will implement it by yourself. ES2020 features such an optional chaining are available in Vue 3, but not Vue 2.x.

More information can be found here

I believe "vue-i18n": "^8.22.1" (git) you are using is not compatible with Vue 3 due to a major changes how Vue 3 works with regards to plugins (not very clear from the readme for sure). You can try vue-i18n-next which is Vue 3 "ready" but still in beta stage....

Also, when using v8.x with Vue 2, be sure to create instance with new keyword - const i18n = new VueI18n() (it's a class)

...if you are new to Vue, it would be probably better for you to work with Vue 2. Vue 3 is pretty new (released few days ago) and most of the ecosystem (all sorts of plugins and component libraries) is not ready for it yet. And you probably don't need all the new stuff. Start with v2, enjoy it's stable ecosystem and lots of learning resources on the internet and switch to v3 when all the tools you need make transition to v3 ....

The dialog method dialog.showSaveDialog returns a promise which resolves to an object, it does not return a string:

dialog.showSaveDialog([browserWindow, ]options)

Returns Promise - Resolve with an object containing the following:

• canceled Boolean - whether or not the dialog was canceled.
• filePath String (optional) - If the dialog is canceled, this will be undefined.
• bookmark String (optional) macOS mas - Base64 encoded string which contains the security scoped bookmark data for the saved file. securityScopedBookmarks must be enabled for this to be present. (For return values, see table here.)

You have to await for dialog.showSaveDialog or use dialog.showSaveDialogSync and also, you can make exportData to be asynchronous rather than creating an inner async function.

Try to refactor your code like this: