wip: defineOptions -> defineProps + defineEmit + useContext

packages/runtime-core/src/apiSetupHelpers.ts

@@ -0,0 +1,60 @@
+import { shallowReadonly } from '@vue/reactivity'
+import { getCurrentInstance, SetupContext } from './component'
+import { EmitFn, EmitsOptions } from './componentEmits'
+import { ComponentObjectPropsOptions, ExtractPropTypes } from './componentProps'
+import { warn } from './warning'
+
+/**
+ * Compile-time-only helper used for declaring props inside `<script setup>`.
+ * This is stripped away in the compiled code and should never be actually
+ * called at runtime.
+ */
+// overload 1: string props
+export function defineProps<
+  TypeProps = undefined,
+  PropNames extends string = string,
+  InferredProps = { [key in PropNames]?: any }
+>(
+  props?: PropNames[]
+): Readonly<TypeProps extends undefined ? InferredProps : TypeProps>
+// overload 2: object props
+export function defineProps<
+  TypeProps = undefined,
+  PP extends ComponentObjectPropsOptions = ComponentObjectPropsOptions,
+  InferredProps = ExtractPropTypes<PP>
+>(props?: PP): Readonly<TypeProps extends undefined ? InferredProps : TypeProps>
+// implementation
+export function defineProps(props?: any) {
+  if (__DEV__ && props) {
+    warn(
+      `defineProps() is a compiler-hint helper that is only usable inside ` +
+        `<script setup> of a single file component. Its arguments should be ` +
+        `compiled away and passing it at runtime has no effect.`
+    )
+  }
+  return __DEV__
+    ? shallowReadonly(getCurrentInstance()!.props)
+    : getCurrentInstance()!.props
+}
+
+export function defineEmit<
+  TypeEmit = undefined,
+  E extends EmitsOptions = EmitsOptions,
+  EE extends string = string,
+  InferredEmit = EmitFn<E>
+>(emitOptions?: E | EE[]): TypeEmit extends undefined ? InferredEmit : TypeEmit
+// implementation
+export function defineEmit(emitOptions?: any) {
+  if (__DEV__ && emitOptions) {
+    warn(
+      `defineEmit() is a compiler-hint helper that is only usable inside ` +
+        `<script setup> of a single file component. Its arguments should be ` +
+        `compiled away and passing it at runtime has no effect.`
+    )
+  }
+  return getCurrentInstance()!.emit
+}
+
+export function useContext(): SetupContext {
+  return getCurrentInstance()!.setupContext!
+}