Migration to Vue 3 Guide

[bencodezen]

The following contains a list of all remaining sections of the migration guide to complete.

Legend

In terms of what the styling means:

• [x] means this has been PR'd and merged
• Bolded means that this is still an item to do
• Normal text with a PR at the end means it's currently in review

Critical

• [x] RFC #19: Global API Treeshaking - PR #144
  • [x] RFC #29: Global mounting / configuration - PR #125
  • [x] RFC #117: Global API updates - PR #125
• [x] RFC #8: Replace v-bind sync with v-model - PR #143

High

• [x] RFC #27: Functional and async components API change - PR #135
  • [x] RFC #148: New Async Component API - PR #139
• [x] RFC #31: Component v-model API change - PR #143
• [x] RFC #154: Attribute fallthrough + functional component updates - PR #141

Medium

• [x] RFC #32: Custom Directive API change - PR #146
• [x] RFC #105: transition API changes - Issue #138
• [x] RFC #118: Remove instance events methods (API removal) - PR #167
• [x] RFC #126: Attribute coercion behavior change - PR #149
• [x] RFC #149: Custom Elements Interop Improvements - PR #177
• [x] RFC #20: Slots Unification - PR #159
• [x] RFC #28: Render function API change and library authors - PR #160

Low

• [x] RFC #95: Remove keycode support in v-on - PR #158
• [x] RFC #97: Remove filters (API removal) - PR #164
• [x] RFC #98: Remove inline-template (API removal) - PR #183
• [x] RFC #111: Remove data object declaration (API removal) - PR #165

New Features

• [x] RFC #78 Composition API - PR #161
• [x] RFC #112 Teleport - PR #161
• [x] RFC #16: Add "emits" component option - PR #161
• [x] Custom Renderer API - PR #161
• [x] Fragments - PR #163

[sodatea]

https://github.com/vuejs/vue-codemod#migrating-from-vue-2-to-vue-3 can be used as a starting point.

[jacekkarczmarczyk]

Not sure if this is the best place to comment but FAQ links to migration helper which looks quite outdated

[NataliaTepluhina]

@jacekkarczmarczyk we will change the link to new migration helper as soon as we have it 😄

[ota-meshi]

Hi! Not included in the RFC, but need to write a migration guide for lifecycle hook changes?

• Removed beforeDestroy and destroyed
• Added beforeUnmount and unmounted

[xPaw]

There should be a section about watch no longer accepting dot-eliminated path strings. https://github.com/vuejs/vue-next/issues/671#issuecomment-579818159

[posva]

I think it's worth documenting the removal of $parent (and $children) as well https://github.com/vuejs/vue-next/issues/2044#issuecomment-687193027

[NataliaTepluhina]

Closing this issue as transition API changes were added to docs and linked on Migration Guide - Introduction via https://github.com/vuejs/docs-next/commit/5d02aad4216bd796f18522fc40f483d099120b4a