@vue/ref-transform
⚠️ This is experimental and currently only provided for testing and feedback. It may break during patches or even be removed. Use at your own risk!Follow https://github.com/vuejs/rfcs/discussions/369 for details and updates.
Basic Rules
-
$()
to turn refs into reative variables -
$$()
to access the original refs from reative variables
import { ref, watch } from 'vue'
// bind ref as a variable
let count = $(ref(0))
// no need for .value
console.log(count)
// get the actual ref
watch($$(count), c => console.log(`count changed to ${c}`))
// assignments are reactive
count++
Shorthands
A few commonly used APIs have shorthands (which also removes the need to import them):
-
$(ref(0))
->$ref(0)
-
$(computed(() => 123))
->$computed(() => 123)
-
$(shallowRef({}))
->$shallowRef({})
API
This package is the lower-level transform that can be used standalone. Higher-level tooling (e.g. @vitejs/plugin-vue
and vue-loader
) will provide integration via options.
shouldTransform
Can be used to do a cheap check to determine whether full transform should be performed.
import { shouldTransform } from '@vue/ref-transform'
shouldTransform(`let a = ref(0)`) // false
shouldTransform(`let a = $ref(0)`) // true
transform
import { transform } from '@vue/ref-transform'
const src = `let a = $ref(0); a++`
const {
code, // import { ref as _ref } from 'vue'; let a = (ref(0)); a.value++"
map
} = transform(src, {
filename: 'foo.ts',
sourceMap: true,
// @babel/parser plugins to enable.
// 'typescript' and 'jsx' will be auto-inferred from filename if provided,
// so in most cases explicit parserPlugins are not necessary
parserPlugins: [/* ... */]
})
Options
interface RefTransformOptions {
filename?: string
sourceMap?: boolean // default: false
parserPlugins?: ParserPlugin[]
importHelpersFrom?: string // default: "vue"
}
transformAST
Transform with an existing Babel AST + MagicString instance. This is used internally by @vue/compiler-sfc
to avoid double parse/transform cost.
import { transformAST } from '@vue/ref-transform'
import { parse } from '@babel/parser'
import MagicString from 'magic-string'
const src = `let a = $ref(0); a++`
const ast = parse(src, { sourceType: 'module' })
const s = new MagicString(src)
const {
rootVars, // ['a']
importedHelpers // ['ref']
} = transformAST(ast, s)
console.log(s.toString()) // let a = _ref(0); a.value++