feat(RadioGroup): add direction prop

src/radio-group/index.js

@@ -9,6 +9,7 @@ export default createComponent({
   props: {
     value: null,
     disabled: Boolean,
+    direction: String,
     checkedColor: String,
     iconSize: [Number, String],
   },
@@ -21,7 +22,7 @@ export default createComponent({
 
   render() {
     return (
-      <div class={bem()} role="radiogroup">
+      <div class={bem([this.direction])} role="radiogroup">
         {this.slots()}
       </div>
     );

src/radio-group/index.less

@@ -0,0 +1,8 @@
+@import '../style/var';
+
+.van-radio-group {
+  &--horizontal {
+    display: flex;
+    flex-wrap: wrap;
+  }
+}