feat(Slider): add button-size prop

src/slider/test/__snapshots__/index.spec.js.snap

@@ -1,6 +1,6 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
-exports[`bar height 1`] = `
+exports[`bar-height prop 1`] = `
 <div class="van-slider">
   <div class="van-slider__bar" style="width: 50%; height: 10px;">
     <div role="slider" tabindex="0" aria-valuemin="0" aria-valuenow="50" aria-valuemax="100" aria-orientation="horizontal" class="van-slider__button-wrapper">
@@ -10,6 +10,16 @@ exports[`bar height 1`] = `
 </div>
 `;
 
+exports[`button-size prop 1`] = `
+<div class="van-slider">
+  <div class="van-slider__bar" style="width: 50%; height: 2px;">
+    <div role="slider" tabindex="0" aria-valuemin="0" aria-valuenow="50" aria-valuemax="100" aria-orientation="horizontal" class="van-slider__button-wrapper">
+      <div class="van-slider__button" style="width: 10px; height: 10px;"></div>
+    </div>
+  </div>
+</div>
+`;
+
 exports[`click bar 1`] = `
 <div class="van-slider van-slider--disabled">
   <div class="van-slider__bar" style="width: 50%; height: 2px;">

src/slider/test/index.spec.js

@@ -111,7 +111,7 @@ it('click vertical', () => {
   restoreMock();
 });
 
-it('bar height', () => {
+it('bar-height prop', () => {
   const wrapper = mount(Slider, {
     propsData: {
       value: 50,
@@ -122,6 +122,17 @@ it('bar height', () => {
   expect(wrapper).toMatchSnapshot();
 });
 
+it('button-size prop', () => {
+  const wrapper = mount(Slider, {
+    propsData: {
+      value: 50,
+      buttonSize: 10,
+    },
+  });
+
+  expect(wrapper).toMatchSnapshot();
+});
+
 it('should not emit change event when value not changed', () => {
   const wrapper = mount(Slider, {
     propsData: {