youzan · rex-zsd · Sep 22, 2020 · Sep 22, 2020
diff --git a/packages/common/utils.ts b/packages/common/utils.ts
@@ -21,7 +21,7 @@ export function nextTick(fn: Function) {
   }, 1000 / 30);
 }
 
-let systemInfo: WechatMiniprogram.GetSystemInfoSyncResult = null;
+let systemInfo: WechatMiniprogram.GetSystemInfoSyncResult;
 export function getSystemInfoSync() {
   if (systemInfo == null) {
     systemInfo = wx.getSystemInfoSync();
@@ -54,3 +54,29 @@ export function requestAnimationFrame(cb: Function) {
       cb();
     });
 }
+
+export function getRect(
+  this: WechatMiniprogram.Component.TrivialInstance,
+  selector: string
+): Promise<WechatMiniprogram.BoundingClientRectCallbackResult> {
+  return new Promise((resolve) => {
+    wx.createSelectorQuery()
+      .in(this)
+      .select(selector)
+      .boundingClientRect()
+      .exec((rect = []) => resolve(rect[0]));
+  });
+}
+
+export function getAllRect(
+  this: WechatMiniprogram.Component.TrivialInstance,
+  selector: string
+): Promise<WechatMiniprogram.BoundingClientRectCallbackResult[]> {
+  return new Promise((resolve) => {
+    wx.createSelectorQuery()
+      .in(this)
+      .selectAll(selector)
+      .boundingClientRect()
+      .exec((rect = []) => resolve(rect[0]));
+  });
+}
diff --git a/packages/tabs/index.ts b/packages/tabs/index.ts
@@ -1,7 +1,7 @@
 import { VantComponent } from '../common/component';
 import { touch } from '../mixins/touch';
 import { Weapp } from 'definitions/weapp';
-import { isDef, addUnit } from '../common/utils';
+import { getAllRect, getRect, isDef } from '../common/utils';
 
 type TrivialInstance = WechatMiniprogram.Component.TrivialInstance;
 
@@ -35,10 +35,7 @@ VantComponent({
     swipeable: Boolean,
     titleActiveColor: String,
     titleInactiveColor: String,
-    color: {
-      type: String,
-      observer: 'setLine',
-    },
+    color: String,
     animated: {
       type: Boolean,
       observer() {
@@ -55,7 +52,6 @@ VantComponent({
     lineHeight: {
       type: [String, Number],
       value: -1,
-      observer: 'setLine',
     },
     active: {
       type: [String, Number],
@@ -102,13 +98,15 @@ VantComponent({
   },
 
   data: {
-    tabs: [],
+    tabs: [] as Record<string, unknown>[],
     lineStyle: '',
     scrollLeft: 0,
     scrollable: false,
     trackStyle: '',
-    currentIndex: null,
+    currentIndex: 0,
     container: null,
+    skipTransition: true,
+    lineOffsetLeft: 0,
   },
 
   mounted() {
@@ -223,54 +221,34 @@ VantComponent({
       }
     },
 
-    setLine(skipTransition?: boolean) {
+    setLine(skipTransition = false) {
       if (this.data.type !== 'line') {
         return;
       }
 
-      const {
-        color,
-        duration,
-        currentIndex,
-        lineWidth,
-        lineHeight,
-      } = this.data;
-
-      this.getRect('.van-tab', true).then(
-        (rects: WechatMiniprogram.BoundingClientRectCallbackResult[] = []) => {
-          const rect = rects[currentIndex];
-          if (rect == null) {
-            return;
-          }
-          const height =
-            lineHeight !== -1
-              ? `height: ${addUnit(lineHeight)}; border-radius: ${addUnit(
-                  lineHeight
-                )};`
-              : '';
-
-          let left = rects
-            .slice(0, currentIndex)
-            .reduce((prev, curr) => prev + curr.width, 0);
-
-          left += (rect.width - lineWidth) / 2;
-
-          const transition = skipTransition
-            ? ''
-            : `transition-duration: ${duration}s; -webkit-transition-duration: ${duration}s;`;
-
-          this.setData({
-            lineStyle: `
-            ${height}
-            width: ${addUnit(lineWidth)};
-            background-color: ${color};
-            -webkit-transform: translateX(${left}px);
-            transform: translateX(${left}px);
-            ${transition}
-          `,
-          });
+      const { currentIndex } = this.data;
+
+      Promise.all([
+        getAllRect.call(this, '.van-tab'),
+        getRect.call(this, '.van-tabs__line'),
+      ]).then(([rects = [], lineRect]) => {
+        const rect = rects[currentIndex];
+
+        if (rect == null) {
+          return;
         }
-      );
+
+        let lineOffsetLeft = rects
+          .slice(0, currentIndex)
+          .reduce((prev, curr) => prev + curr.width, 0);
+
+        lineOffsetLeft += (rect.width - lineRect.width) / 2;
+
+        this.setData({
+          lineOffsetLeft,
+          skipTransition,
+        });
+      });
     },
 
     // scroll active tab into view
@@ -282,23 +260,18 @@ VantComponent({
       }
 
       Promise.all([
-        this.getRect('.van-tab', true),
-        this.getRect('.van-tabs__nav'),
-      ]).then(
-        ([tabRects, navRect]: [
-          WechatMiniprogram.BoundingClientRectCallbackResult[],
-          WechatMiniprogram.BoundingClientRectCallbackResult
-        ]) => {
-          const tabRect = tabRects[currentIndex];
-          const offsetLeft = tabRects
-            .slice(0, currentIndex)
-            .reduce((prev, curr) => prev + curr.width, 0);
-
-          this.setData({
-            scrollLeft: offsetLeft - (navRect.width - tabRect.width) / 2,
-          });
-        }
-      );
+        getAllRect.call(this, '.van-tab'),
+        getRect.call(this, '.van-tabs__nav'),
+      ]).then(([tabRects, navRect]) => {
+        const tabRect = tabRects[currentIndex];
+        const offsetLeft = tabRects
+          .slice(0, currentIndex)
+          .reduce((prev, curr) => prev + curr.width, 0);
+
+        this.setData({
+          scrollLeft: offsetLeft - (navRect.width - tabRect.width) / 2,
+        });
+      });
     },
 
     onTouchScroll(event: Weapp.TouchEvent) {

diff --git a/packages/tabs/index.wxml b/packages/tabs/index.wxml
@@ -20,7 +20,7 @@
         style="{{ color ? 'border-color: ' + color : '' }}"
       >
         <view class="{{ utils.bem('tabs__nav', [type, { complete: !ellipsis }]) }} nav-class" style="{{ getters.tabCardTypeBorderStyle(color, type) }}">
-          <view wx:if="{{ type === 'line' }}" class="van-tabs__line" style="{{ lineStyle }}" />
+          <view wx:if="{{ type === 'line' }}" class="van-tabs__line" style="{{ getters.lineStyle({ color, lineOffsetLeft, lineHeight, skipTransition, duration, lineWidth }) }}" />
           <view
             wx:for="{{ tabs }}"
             wx:key="index"
@@ -60,4 +60,4 @@
       <slot />
     </view>
   </view>
-</view>
+</view>
diff --git a/packages/tabs/index.wxs b/packages/tabs/index.wxs
@@ -1,4 +1,6 @@
 /* eslint-disable */
+var utils = require('../wxs/utils.wxs');
+
 function tabClass(active, ellipsis) {
   var classes = ['tab-class'];
 
@@ -68,11 +70,42 @@ function trackStyle(data) {
   return [
     'transform: translate3d(' + -100 * data.currentIndex + '%, 0, 0)',
     '-webkit-transition-duration: ' + data.duration + 's',
-    'transition-duration: ' + data.duration + 's'
+    'transition-duration: ' + data.duration + 's',
   ].join(';');
 }
 
-module.exports.tabClass = tabClass;
-module.exports.tabStyle = tabStyle;
-module.exports.trackStyle = trackStyle;
-module.exports.tabCardTypeBorderStyle = tabCardTypeBorderStyle;
+function lineStyle(data) {
+  var styles = [
+    ['width', utils.addUnit(data.lineWidth)],
+    ['transform', 'translateX(' + data.lineOffsetLeft + 'px)'],
+    ['-webkit-transform', 'translateX(' + data.lineOffsetLeft + 'px)'],
+  ];
+
+  if (data.color) {
+    styles.push(['background-color', data.color]);
+  }
+
+  if (data.lineHeight !== -1) {
+    styles.push(['height', utils.addUnit(data.lineHeight)]);
+    styles.push(['border-radius', utils.addUnit(data.lineHeight)]);
+  }
+
+  if (!data.skipTransition) {
+    styles.push(['transition-duration', data.duration + 's']);
+    styles.push(['-webkit-transition-duration', data.duration + 's']);
+  }
+
+  return styles
+    .map(function (item) {
+      return item.join(':');
+    })
+    .join(';');
+}
+
+module.exports = {
+  tabClass: tabClass,
+  tabStyle: tabStyle,
+  trackStyle: trackStyle,
+  lineStyle: lineStyle,
+  tabCardTypeBorderStyle: tabCardTypeBorderStyle,
+};