[bugfix] Swipe: fix blank area when use width prop (#3751)

src/swipe/README.md

@@ -83,7 +83,7 @@ export default {
 ### Set Swiper Item Size
 
 ```html
-<van-swipe :autoplay="3000" :width="300">
+<van-swipe :loop="false" :width="300">
   <van-swipe-item>1</van-swipe-item>
   <van-swipe-item>2</van-swipe-item>
   <van-swipe-item>3</van-swipe-item>

src/swipe/README.zh-CN.md

@@ -71,8 +71,10 @@ export default {
 
 ### 纵向滚动
 
+设置`vertical`属性后滑块会纵向排列，此时需要指定滑块容器的高度
+
 ```html
-<van-swipe :autoplay="3000" vertical>
+<van-swipe style="height: 200px;" vertical>
   <van-swipe-item>1</van-swipe-item>
   <van-swipe-item>2</van-swipe-item>
   <van-swipe-item>3</van-swipe-item>
@@ -82,8 +84,10 @@ export default {
 
 ### 控制滑块大小
 
+滑块默认宽度为`100%`，可以通过`width`属性设置滑块的宽度，此属性不能与循环播放同时使用
+
 ```html
-<van-swipe :autoplay="3000" :width="300">
+<van-swipe :loop="false" :width="300">
   <van-swipe-item>1</van-swipe-item>
   <van-swipe-item>2</van-swipe-item>
   <van-swipe-item>3</van-swipe-item>
@@ -93,6 +97,8 @@ export default {
 
 ### 自定义指示器
 
+通过`indicator`插槽可以自定义指示器的样式
+
 ```html
 <van-swipe @change="onChange">
   <van-swipe-item>1</van-swipe-item>
@@ -135,8 +141,8 @@ export default {
 | indicator-color | 指示器颜色 | `String` | `#1989fa` | - |
 | vertical | 是否为纵向滚动 | `Boolean` | `false` | - |
 | touchable | 是否可以通过手势滑动 | `Boolean` | `true` | - |
-| width | 滑块宽度 | `Number` | `0` | - |
-| height | 滑块高度 | `Number` | `0` | - |
+| width | 滑块宽度 | `Number` | `auto` | - |
+| height | 滑块高度 | `Number` | `auto` | - |
 
 ### Swipe Events
 

src/swipe/demo/index.vue

@@ -26,7 +26,7 @@
     <demo-block :title="$t('title3')">
       <van-swipe
         indicator-color="white"
-        @change="onChange"
+        @change="onChange1"
       >
         <van-swipe-item>1</van-swipe-item>
         <van-swipe-item>2</van-swipe-item>
@@ -40,6 +40,7 @@
         vertical
         :autoplay="3000"
         indicator-color="white"
+        style="height: 200px;"
         class="demo-swipe--vertical"
       >
         <van-swipe-item>1</van-swipe-item>
@@ -51,7 +52,6 @@
 
     <demo-block :title="$t('title5')">
       <van-swipe
-        :autoplay="3000"
         :width="300"
         :loop="false"
         indicator-color="white"
@@ -64,7 +64,7 @@
     </demo-block>
 
     <demo-block :title="$t('title6')">
-      <van-swipe @change="onChange">
+      <van-swipe @change="onChange2">
         <van-swipe-item>1</van-swipe-item>
         <van-swipe-item>2</van-swipe-item>
         <van-swipe-item>3</van-swipe-item>
@@ -112,9 +112,12 @@ export default {
   },
 
   methods: {
-    onChange(index) {
-      this.current = index;
+    onChange1(index) {
       this.$toast(this.$t('message') + index);
+    },
+
+    onChange2(index) {
+      this.current = index;
     }
   }
 };
@@ -156,8 +159,6 @@ export default {
   }
 
   &--vertical {
-    height: 200px;
-
     .van-swipe-item {
       line-height: 200px;
     }

src/swipe/index.js

@@ -2,6 +2,7 @@ import { createNamespace } from '../utils';
 import { preventDefault } from '../utils/dom/event';
 import { TouchMixin } from '../mixins/touch';
 import { BindEventMixin } from '../mixins/bind-event';
+import { range } from '../utils/format/number';
 
 const [createComponent, bem] = createNamespace('swipe');
 
@@ -116,6 +117,11 @@ export default createComponent({
       return {
         backgroundColor: this.indicatorColor
       };
+    },
+
+    minOffset() {
+      const rect = this.$el.getBoundingClientRect();
+      return (this.vertical ? rect.height : rect.width) - this.size * this.count;
     }
   },
 
@@ -123,11 +129,13 @@ export default createComponent({
     // initialize swipe position
     initialize(active = this.initialSwipe) {
       clearTimeout(this.timer);
+
       if (this.$el) {
         const rect = this.$el.getBoundingClientRect();
         this.computedWidth = this.width || rect.width;
         this.computedHeight = this.height || rect.height;
       }
+
       this.swiping = true;
       this.active = active;
       this.offset = this.count > 1 ? -this.size * this.active : 0;
@@ -157,7 +165,7 @@ export default createComponent({
 
       if (this.isCorrectDirection) {
         preventDefault(event, true);
-        this.move({ offset: Math.min(Math.max(this.delta, -this.size), this.size) });
+        this.move({ offset: this.delta });
       }
     },
 
@@ -176,41 +184,70 @@ export default createComponent({
       this.autoPlay();
     },
 
-    move({ pace = 0, offset = 0, emitChange }) {
-      const { delta, active, count, swipes, trackSize } = this;
-      const atFirst = active === 0;
-      const atLast = active === count - 1;
-      const outOfBounds =
-        !this.loop &&
-        ((atFirst && (offset > 0 || pace < 0)) || (atLast && (offset < 0 || pace > 0)));
+    getTargetActive(pace) {
+      const { active, count } = this;
 
-      if (outOfBounds || count <= 1) {
+      if (pace) {
+        if (this.loop) {
+          return range(active + pace, -1, count);
+        }
+
+        return range(active + pace, 0, count - 1);
+      }
+
+      return active;
+    },
+
+    getTargetOffset(targetActive, offset) {
+      let currentPosition = targetActive * this.size;
+      if (!this.loop) {
+        currentPosition = Math.min(currentPosition, -this.minOffset);
+      }
+
+      let targetOffset = Math.round(offset - currentPosition);
+      if (!this.loop) {
+        targetOffset = range(targetOffset, this.minOffset, 0);
+      }
+
+      return targetOffset;
+    },
+
+    move({ pace = 0, offset = 0, emitChange }) {
+      const { loop, count, active, swipes, trackSize, minOffset } = this;
+
+      if (count <= 1) {
         return;
       }
 
+      const targetActive = this.getTargetActive(pace);
+      const targetOffset = this.getTargetOffset(targetActive, offset);
+
+      // auto move first and last swipe in loop mode
+      if (loop) {
         if (swipes[0]) {
-        swipes[0].offset = atLast && (delta < 0 || pace > 0) ? trackSize : 0;
+          const outRightBound = targetOffset < minOffset;
+          swipes[0].offset = outRightBound ? trackSize : 0;
         }
 
         if (swipes[count - 1]) {
-        swipes[count - 1].offset = atFirst && (delta > 0 || pace < 0) ? -trackSize : 0;
+          const outLeftBound = targetOffset > 0;
+          swipes[count - 1].offset = outLeftBound ? -trackSize : 0;
+        }
       }
 
-      if (pace && active + pace >= -1 && active + pace <= count) {
-        this.active += pace;
+      this.active = targetActive;
+      this.offset = targetOffset;
 
-        if (emitChange) {
+      if (emitChange && targetActive !== active) {
         this.$emit('change', this.activeIndicator);
       }
-      }
-
-      this.offset = Math.round(offset - this.active * this.size);
     },
 
     swipeTo(index) {
       this.swiping = true;
       this.resetTouchStatus();
       this.correctPosition();
+
       setTimeout(() => {
         this.swiping = false;
         this.move({

src/swipe/test/__snapshots__/demo.spec.js.snap

@@ -36,7 +36,7 @@ exports[`renders demo correctly 1`] = `
     </div>
   </div>
   <div>
-    <div class="demo-swipe--vertical van-swipe">
+    <div class="demo-swipe--vertical van-swipe" style="height: 200px;">
       <div class="van-swipe__track" style="height: 400px; transition-duration: 0ms; transform: translateY(0px);">
         <div class="van-swipe-item" style="width: 100px; height: 100px; transform: translateY(0px);">1</div>
         <div class="van-swipe-item" style="width: 100px; height: 100px; transform: translateY(0px);">2</div>