[improvement] functional inherit context (#2716)

packages/utils/use/sfc.ts

@@ -0,0 +1,53 @@
+/**
+ * Create a basic component with common options
+ */
+import '../../locale';
+import { camelize } from '..';
+import SlotsMixin from '../../mixins/slots';
+import Vue, { VueConstructor, ComponentOptions } from 'vue';
+
+type VantComponentOptions = ComponentOptions<Vue> & {
+  functional?: boolean;
+  install?: (Vue: VueConstructor) => void;
+};
+
+const arrayProp = {
+  type: Array,
+  default: () => []
+};
+
+const numberProp = {
+  type: Number,
+  default: 0
+};
+
+function defaultProps(props: any) {
+  Object.keys(props).forEach(key => {
+    if (props[key] === Array) {
+      props[key] = arrayProp;
+    } else if (props[key] === Number) {
+      props[key] = numberProp;
+    }
+  });
+}
+
+function install(this: ComponentOptions<Vue>, Vue: VueConstructor) {
+  const { name } = this;
+  if (name) {
+    Vue.component(name, this);
+    Vue.component(camelize(`-${name}`), this);
+  }
+}
+
+export default (name: string) => (sfc: VantComponentOptions) => {
+  sfc.name = name;
+  sfc.install = install;
+  sfc.mixins = sfc.mixins || [];
+  sfc.mixins.push(SlotsMixin);
+
+  if (sfc.props) {
+    defaultProps(sfc.props);
+  }
+
+  return sfc;
+};