feat(Slider): add slide animation (#4700)

src/slider/index.js

@@ -34,6 +34,12 @@ export default createComponent({
     }
   },
 
+  data() {
+    return {
+      dragStatus: ''
+    };
+  },
+
   computed: {
     range() {
       return this.max - this.min;
@@ -139,6 +145,10 @@ export default createComponent({
       background: this.activeColor
     };
 
+    if (this.dragStatus) {
+      barStyle.transition = 'none';
+    }
+
     return (
       <div
         style={style}

src/slider/index.less

@@ -9,6 +9,7 @@
     position: relative;
     background-color: @slider-active-background-color;
     border-radius: inherit;
+    transition: width @animation-duration-fast;
   }
 
   &__button {