Migrate from Vue 2 to Vue 3

[The4thLaw]

Summary
Vue 2 will only be supported until end of 2023. We should migrate to Vue 3 now that most libraries have been adapted.

Documentation links

• https://v3-migration.vuejs.org/
• https://vuejs.org/guide/typescript/overview#general-usage-notes (might be interesting to include preliminary TS support so that we can migrate little by little)
• https://v3-migration.vuejs.org/breaking-changes/data-option.html#mixin-merge-behavior-change (mixins might require some work or have to be transformed into composables)
• https://stackoverflow.com/questions/76710487/migartion-of-vue2-to-vue-3-how-to-update-the-mixins-added-in-vue2-components-i (idem)
• https://vuetifyjs.com/en/getting-started/upgrade-guide/

Points of attention

• Vuetify must be migrated at the same time. We must check that all components we need are supported (not all v2 components are supported in v3 at the time this issue is created)
  • Icon fonts require a bit more work to be tree-shaken https://vuetifyjs.com/en/features/icon-fonts/

Alternatives
Some components are no longer supported. An alternative must be found.

• vue-meta has a v3 alpha version, but that version has seen no update for over a year. It's not clear whether it will remain supported
  • https://unhead.unjs.io/setup/vue/installation#optional-vue-3-options-api
  • We have to be careful to keep the title templace (supported by usehead) and link to the manifest
• Portals though still supported, will probably be replaced by the Teleport component. According to the Portal documentation:

  What about Vue 3's Teleport?
  Good question! For most scenario's, you might not even need portal-vue, since the new Teleport component does it better than this library does (read: Without the caveats).

• tiptap-vuetify
  • https://www.tiny.cloud/solutions/wysiwyg-vue-rich-text-editor/
  • https://github.com/yikoyu/vuetify-pro-tiptap
• v-img
  • https://github.com/XiongAmao/vue-easy-lightbox

Potentially useful tools

• https://github.com/unplugin/unplugin-vue-components
• https://github.com/unplugin/unplugin-auto-import