[improvement] unify mixin name (#2795)

packages/utils/use/bem.ts

@@ -36,7 +36,7 @@ function prefix(name: string, mods: Mods): Mods {
   return ret;
 }
 
-export default (name: string) => (el?: Mods, mods?: Mods): Mods => {
+export const useBEM = (name: string) => (el?: Mods, mods?: Mods): Mods => {
   if (el && typeof el !== 'string') {
     mods = el;
     el = '';

packages/utils/use/i18n.ts

@@ -1,7 +1,7 @@
 import { get, camelize } from '..';
 import locale from '../../locale';
 
-export default (name: string) => {
+export const useI18N = (name: string) => {
   const prefix = camelize(name) + '.';
   return (path: string, ...args: any[]): string => {
     const message = get(locale.messages(), prefix + path) || get(locale.messages(), path);

packages/utils/use/index.ts

@@ -1,14 +1,14 @@
-import useBem from './bem';
-import useSfc from './sfc';
-import useI18n from './i18n';
+import { useBEM } from './bem';
+import { useSFC } from './sfc';
+import { useI18N } from './i18n';
 
 type UseReturn = [
-  ReturnType<typeof useSfc>,
-  ReturnType<typeof useBem>,
-  ReturnType<typeof useI18n>
+  ReturnType<typeof useSFC>,
+  ReturnType<typeof useBEM>,
+  ReturnType<typeof useI18N>
 ];
 
 export function use(name: string): UseReturn {
   name = 'van-' + name;
-  return [useSfc(name), useBem(name), useI18n(name)];
+  return [useSFC(name), useBEM(name), useI18N(name)];
 }

packages/utils/use/sfc.ts

@@ -3,7 +3,7 @@
  */
 import '../../locale';
 import { camelize } from '..';
-import SlotsMixin from '../../mixins/slots';
+import { SlotsMixin } from '../../mixins/slots';
 import Vue, {
   VueConstructor,
   ComponentOptions,
@@ -35,7 +35,7 @@ export interface VantComponentOptions extends ComponentOptions<Vue> {
 
 export type DefaultProps = Record<string, any>;
 
-export type FunctionalComponent<
+export type FunctionComponent<
   Props = DefaultProps,
   PropDefs = PropsDefinition<Props>
 > = {
@@ -93,6 +93,7 @@ function install(this: ComponentOptions<Vue>, Vue: VueConstructor) {
 
 // unify slots & scopedSlots
 export function unifySlots(context: RenderContext) {
+  // use data.scopedSlots in lower Vue version
   const scopedSlots = context.scopedSlots || context.data.scopedSlots || {};
   const slots = context.slots();
 
@@ -105,8 +106,9 @@ export function unifySlots(context: RenderContext) {
   return scopedSlots;
 }
 
-function transformFunctionalComponent(
-  pure: FunctionalComponent
+// should be removed after Vue 3
+function transformFunctionComponent(
+  pure: FunctionComponent
 ): VantComponentOptions {
   return {
     functional: true,
@@ -117,11 +119,11 @@ function transformFunctionalComponent(
   };
 }
 
-export default (name: string) => <Props = DefaultProps, Events = {}, Slots = {}>(
-  sfc: VantComponentOptions | FunctionalComponent
+export const useSFC = (name: string) => <Props = DefaultProps, Events = {}, Slots = {}>(
+  sfc: VantComponentOptions | FunctionComponent
 ): TsxComponent<Props, Events, Slots> => {
   if (typeof sfc === 'function') {
-    sfc = transformFunctionalComponent(sfc);
+    sfc = transformFunctionComponent(sfc);
   }
 
   if (!sfc.functional) {