49bb44756f
BREAKING CHANGE: watch APIs now default to use `flush: 'pre'` instead of
`flush: 'post'`.
- This change affects `watch`, `watchEffect`, the `watch` component
option, and `this.$watch`.
- As pointed out by @skirtles-code in
[this comment](https://github.com/vuejs/vue-next/issues/1706#issuecomment-666258948),
Vue 2's watch behavior is pre-flush, and the ecosystem has many uses
of watch that assumes the pre-flush behavior. Defaulting to post-flush
can result in unnecessary re-renders without the users being aware of
it.
- With this change, watchers need to specify `{ flush: 'post' }` via
options to trigger callback after Vue render updates. Note that
specifying `{ flush: 'post' }` will also defer `watchEffect`'s
initial run to wait for the component's initial render.
@vue/runtime-core
This package is published only for typing and building custom renderers. It is NOT meant to be used in applications.
For full exposed APIs, see src/index.ts. You can also run yarn build runtime-core --types from repo root, which will generate an API report at temp/runtime-core.api.md.
Building a Custom Renderer
import { createRenderer } from '@vue/runtime-core'
const { render, createApp } = createRenderer({
patchProp,
insert,
remove,
createElement,
// ...
})
// `render` is the low-level API
// `createApp` returns an app instance with configurable context shared
// by the entire app tree.
export { render, createApp }
export * from '@vue/runtime-core'
See @vue/runtime-dom for how a DOM-targeting renderer is implemented.