[improvement] Functional components be just functions (#2735)

packages/utils/functional.ts

@@ -1,5 +1,4 @@
 import { RenderContext, VNodeData } from 'vue/types';
-import { ScopedSlot } from 'vue/types/vnode';
 
 type ObjectIndex = {
   [key: string]: any;
@@ -47,17 +46,3 @@ export function emit(context: Context, eventName: string, ...args: any[]) {
     }
   }
 }
-
-// unify slots & scopedSlots
-export function unifySlots(context: Context) {
-  const { scopedSlots } = context;
-  const slots = context.slots();
-
-  Object.keys(slots).forEach(key => {
-    if (!scopedSlots[key]) {
-      scopedSlots[key] = () => slots[key];
-    }
-  });
-
-  return scopedSlots;
-}

packages/utils/use/sfc.ts

@@ -4,13 +4,29 @@
 import '../../locale';
 import { camelize } from '..';
 import SlotsMixin from '../../mixins/slots';
-import Vue, { VueConstructor, ComponentOptions } from 'vue';
+import Vue, {
+  VueConstructor,
+  ComponentOptions,
+  CreateElement,
+  RenderContext
+} from 'vue/types';
+import { VNode, ScopedSlot } from 'vue/types/vnode';
 
 type VantComponentOptions = ComponentOptions<Vue> & {
   functional?: boolean;
   install?: (Vue: VueConstructor) => void;
 };
 
+type VantPureComponent = {
+  (
+    h: CreateElement,
+    props: { [key: string]: any },
+    slots: { [key: string]: ScopedSlot | undefined },
+    context: RenderContext
+  ): VNode;
+  props: any;
+};
+
 const arrayProp = {
   type: Array,
   default: () => []
@@ -39,15 +55,46 @@ function install(this: ComponentOptions<Vue>, Vue: VueConstructor) {
   }
 }
 
-export default (name: string) => (sfc: VantComponentOptions) => {
-  sfc.name = name;
-  sfc.install = install;
-  sfc.mixins = sfc.mixins || [];
-  sfc.mixins.push(SlotsMixin);
+// unify slots & scopedSlots
+export function unifySlots(context: RenderContext) {
+  const { scopedSlots } = context;
+  const slots = context.slots();
+
+  Object.keys(slots).forEach(key => {
+    if (!scopedSlots[key]) {
+      scopedSlots[key] = () => slots[key];
+    }
+  });
+
+  return scopedSlots;
+}
+
+function transformPureComponent(pure: VantPureComponent): VantComponentOptions {
+  return {
+    functional: true,
+    props: pure.props,
+    render: (h, context) => pure(h, context.props, unifySlots(context), context)
+  };
+}
+
+export default (name: string) => (
+  sfc: VantComponentOptions | VantPureComponent
+) => {
+  if (typeof sfc === 'function') {
+    sfc = transformPureComponent(sfc);
+  }
+
+  if (!sfc.functional) {
+    sfc.mixins = sfc.mixins || [];
+    sfc.mixins.push(SlotsMixin);
+  }
 
   if (sfc.props) {
     defaultProps(sfc.props);
   }
 
+  sfc.name = name;
+  sfc.install = install;
+
   return sfc;
 };