BREAKING CHANGE: optionMergeStrategies functions no longer receive
the component instance as the 3rd argument. The argument was technically
internal in Vue 2 and only used for generating warnings, and should not
be needed in userland code. This removal enables much more efficient
caching of option merging.
fix#2225
The previous props/emits normlaization was caching normalized result per
app instance, but during SSR there is a new app instance created for
every request.
The fix now de-opts props/emits normlaization caching when there are
props/emits declared in global mixins - which is a very rare use case.
returned from `defineComponent`
ref: https://github.com/vuejs/vue-router-next/pull/421
also close#1880
Previous `Component` type is now exported as `ConcreteComponent`.
This introduces a minor breaking change when calling `h(comp, { ... })`
will now fail if `comp` is a of generic `Component` type, since it does
not specify what props it expects.
e.g. by replacing `__VUE_OPTIONS_API__` to `false` using webpack's
`DefinePlugin`, the final bundle will drop all code supporting the
options API.
This does not break existing usage, but requires the user to explicitly
configure the feature flags via bundlers to properly tree-shake the
disabled branches. As a result, users will see a console warning if
the flags have not been properly configured.
Note the behavior is different from Vue 2:
- merge strategies no longer apply to built-in options.
- the default value is now an empty object and no longer exposes merge
strategies for built-in options.
BREAKING CHANGE: `createApp` API has been adjusted.
- `createApp()` now accepts the root component, and optionally a props
object to pass to the root component.
- `app.mount()` now accepts a single argument (the root container)
- `app.unmount()` no longer requires arguments.
New behavior looks like the following:
``` js
const app = createApp(RootComponent)
app.mount('#app')
app.unmount()
```
