diff --git a/dist/dropdown-item/index.js b/dist/dropdown-item/index.js
index 529de0f5..f2b6c481 100644
--- a/dist/dropdown-item/index.js
+++ b/dist/dropdown-item/index.js
@@ -6,19 +6,30 @@ VantComponent({
         type: 'ancestor',
         linked(target) {
             this.parent = target;
+            this.updateDataFromParent();
         },
         unlinked() {
             this.parent = null;
         }
     },
     props: {
-        value: null,
-        title: String,
+        value: {
+            type: null,
+            observer: 'rerender'
+        },
+        title: {
+            type: String,
+            observer: 'rerender'
+        },
         disabled: Boolean,
-        titleClass: String,
+        titleClass: {
+            type: String,
+            observer: 'rerender'
+        },
         options: {
             type: Array,
-            value: []
+            value: [],
+            observer: 'rerender'
         }
     },
     data: {
@@ -27,44 +38,67 @@ VantComponent({
         showWrapper: false,
         displayTitle: ''
     },
-    created() {
-        this.setData({ displayTitle: this.computedDisplayTitle(this.data.value) });
-    },
     methods: {
-        computedDisplayTitle(curValue) {
-            const { title, options } = this.data;
-            if (title) {
-                return title;
+        rerender() {
+            wx.nextTick(() => {
+                this.parent && this.parent.updateItemListData();
+            });
+        },
+        updateDataFromParent() {
+            if (this.parent) {
+                const { overlay, duration, activeColor, closeOnClickOverlay, direction } = this.parent.data;
+                this.setData({
+                    overlay,
+                    duration,
+                    activeColor,
+                    closeOnClickOverlay,
+                    direction
+                });
             }
-            const match = options.filter(option => option.value === curValue);
-            const displayTitle = match.length ? match[0].text : '';
-            return displayTitle;
         },
         onClickOverlay() {
             this.toggle();
             this.$emit('close');
         },
         onOptionTap(event) {
-            let { value, displayTitle } = this.data;
             const { option } = event.currentTarget.dataset;
-            const { value: optionValue } = option;
-            if (optionValue !== value) {
-                value = optionValue;
-                displayTitle = this.computedDisplayTitle(optionValue);
-                this.$emit('change', optionValue);
-            }
-            this.setData({ showPopup: false, value, displayTitle });
-            const time = this.data.duration || 0;
+            const { value } = option;
+            const shouldEmitChange = this.data.value !== value;
+            this.setData({ showPopup: false, value });
             setTimeout(() => {
                 this.setData({ showWrapper: false });
-            }, time);
-            // parent 中的 itemListData 是 children 上的数据的集合
-            // 数据的更新由 children 各自维护，但是模板的更新需要额外触发 parent 的 setData
-            this.parent.setData({ itemListData: this.parent.data.itemListData });
+            }, this.data.duration || 0);
+            this.rerender();
+            if (shouldEmitChange) {
+                this.$emit('change', value);
+            }
         },
-        toggle() {
-            const { childIndex } = this.data;
-            this.parent.toggleItem(childIndex);
+        toggle(show, options = {}) {
+            const { showPopup, duration } = this.data;
+            if (show == null) {
+                show = !showPopup;
+            }
+            if (show === showPopup) {
+                return;
+            }
+            if (!show) {
+                const time = options.immediate ? 0 : duration;
+                this.setData({ transition: !options.immediate, showPopup: show });
+                setTimeout(() => {
+                    this.setData({ showWrapper: false });
+                }, time);
+                this.rerender();
+                return;
+            }
+            this.parent.getChildWrapperStyle().then((wrapperStyle = '') => {
+                this.setData({
+                    transition: !options.immediate,
+                    showPopup: show,
+                    wrapperStyle,
+                    showWrapper: true
+                });
+                this.rerender();
+            });
         }
     }
 });
diff --git a/dist/dropdown-menu/index.js b/dist/dropdown-menu/index.js
index 302659a1..889387be 100644
--- a/dist/dropdown-menu/index.js
+++ b/dist/dropdown-menu/index.js
@@ -7,33 +7,23 @@ VantComponent({
         name: 'dropdown-item',
         type: 'descendant',
         linked(target) {
-            this.children = this.children || [];
-            // 透传 props 给 dropdown-item
-            const { overlay, duration, activeColor, closeOnClickOverlay, direction } = this.data;
-            this.updateChildData(target, {
-                overlay,
-                duration,
-                activeColor,
-                closeOnClickOverlay,
-                direction,
-                childIndex: this.children.length
-            });
             this.children.push(target);
-            // 收集 dorpdown-item 的 data 挂在 data 上
-            target &&
-                this.setData({
-                    itemListData: this.data.itemListData.concat([target.data])
-                });
+            this.updateItemListData();
         },
         unlinked(target) {
             this.children = this.children.filter((child) => child !== target);
+            this.updateItemListData();
         }
     },
     props: {
-        activeColor: String,
+        activeColor: {
+            type: String,
+            observer: 'updateChildrenData'
+        },
         overlay: {
             type: Boolean,
-            value: true
+            value: true,
+            observer: 'updateChildrenData'
         },
         zIndex: {
             type: Number,
@@ -41,15 +31,18 @@ VantComponent({
         },
         duration: {
             type: Number,
-            value: 200
+            value: 200,
+            observer: 'updateChildrenData'
         },
         direction: {
             type: String,
-            value: 'down'
+            value: 'down',
+            observer: 'updateChildrenData'
         },
         closeOnClickOverlay: {
             type: Boolean,
-            value: true
+            value: true,
+            observer: 'updateChildrenData'
         },
         closeOnClickOutside: {
             type: Boolean,
@@ -59,68 +52,47 @@ VantComponent({
     data: {
         itemListData: []
     },
-    created() {
+    beforeCreate() {
+        const { windowHeight } = wx.getSystemInfoSync();
+        this.windowHeight = windowHeight;
+        this.children = [];
         ARRAY.push(this);
     },
     destroyed() {
         ARRAY = ARRAY.filter(item => item !== this);
     },
     methods: {
-        updateChildData(childItem, newData, needRefreshList = false) {
-            childItem.setData(newData);
-            if (needRefreshList) {
-                // dropdown-item data 更新，涉及到 title 的展示，触发模板更新
-                this.setData({ itemListData: this.data.itemListData });
-            }
+        updateItemListData() {
+            this.setData({
+                itemListData: this.children.map((child) => child.data)
+            });
+        },
+        updateChildrenData() {
+            this.children.forEach((child) => {
+                child.updateDataFromParent();
+            });
         },
         toggleItem(active) {
             this.children.forEach((item, index) => {
                 const { showPopup } = item.data;
                 if (index === active) {
-                    this.toggleChildItem(item);
+                    item.toggle();
                 }
                 else if (showPopup) {
-                    this.toggleChildItem(item, false, { immediate: true });
+                    item.toggle(false, { immediate: true });
                 }
             });
         },
-        toggleChildItem(childItem, show, options = {}) {
-            const { showPopup, duration } = childItem.data;
-            if (show === undefined)
-                show = !showPopup;
-            if (show === showPopup) {
-                return;
-            }
-            const newChildData = { transition: !options.immediate, showPopup: show };
-            if (!show) {
-                const time = options.immediate ? 0 : duration;
-                this.updateChildData(childItem, Object.assign({}, newChildData), true);
-                setTimeout(() => {
-                    this.updateChildData(childItem, { showWrapper: false }, true);
-                }, time);
-                return;
-            }
-            this.getChildWrapperStyle().then((wrapperStyle = '') => {
-                this.updateChildData(childItem, Object.assign(Object.assign({}, newChildData), { wrapperStyle, showWrapper: true }), true);
-            });
-        },
         close() {
-            this.children.forEach((item) => {
-                this.toggleChildItem(item, false, { immediate: true });
+            this.children.forEach((child) => {
+                child.toggle(false, { immediate: true });
             });
         },
         getChildWrapperStyle() {
-            const { windowHeight } = wx.getSystemInfoSync();
             const { zIndex, direction } = this.data;
-            let offset = 0;
-            return this.getRect('.van-dropdown-menu').then(rect => {
+            return this.getRect('.van-dropdown-menu').then((rect) => {
                 const { top = 0, bottom = 0 } = rect;
-                if (direction === 'down') {
-                    offset = bottom;
-                }
-                else {
-                    offset = windowHeight - top;
-                }
+                const offset = direction === 'down' ? bottom : this.windowHeight - top;
                 let wrapperStyle = `z-index: ${zIndex};`;
                 if (direction === 'down') {
                     wrapperStyle += `top: ${addUnit(offset)};`;
@@ -128,16 +100,17 @@ VantComponent({
                 else {
                     wrapperStyle += `bottom: ${addUnit(offset)};`;
                 }
-                return Promise.resolve(wrapperStyle);
+                return wrapperStyle;
             });
         },
         onTitleTap(event) {
-            // item ---> dropdown-item
-            const { item, index } = event.currentTarget.dataset;
-            if (!item.disabled) {
-                // menuItem ---> dropdown-menu
+            const { index } = event.currentTarget.dataset;
+            const child = this.children[index];
+            if (!child.data.disabled) {
                 ARRAY.forEach(menuItem => {
-                    if (menuItem && menuItem.data.closeOnClickOutside && menuItem !== this) {
+                    if (menuItem &&
+                        menuItem.data.closeOnClickOutside &&
+                        menuItem !== this) {
                         menuItem.close();
                     }
                 });
diff --git a/dist/dropdown-menu/index.wxml b/dist/dropdown-menu/index.wxml
index 22933b57..037ac3b6 100644
--- a/dist/dropdown-menu/index.wxml
+++ b/dist/dropdown-menu/index.wxml
@@ -1,10 +1,10 @@
 <wxs src="../wxs/utils.wxs" module="utils" />
+<wxs src="./index.wxs" module="computed" />
 
 <view class="van-dropdown-menu van-dropdown-menu--top-bottom">
   <view
     wx:for="{{ itemListData }}"
     wx:key="index"
-    data-item="{{ item }}"
     data-index="{{ index }}"
     class="{{ utils.bem('dropdown-menu__item', { disabled: item.disabled }) }}"
     bind:tap="onTitleTap"
@@ -14,7 +14,7 @@
       style="{{ item.showPopup ? 'color:' + activeColor : '' }}"
     >
       <view class="van-ellipsis">
-        {{item.displayTitle}}
+        {{ computed.displayTitle(item) }}
       </view>
     </view>
   </view>
diff --git a/dist/dropdown-menu/index.wxs b/dist/dropdown-menu/index.wxs
new file mode 100644
index 00000000..65388549
--- /dev/null
+++ b/dist/dropdown-menu/index.wxs
@@ -0,0 +1,16 @@
+/* eslint-disable */
+function displayTitle(item) {
+  if (item.title) {
+    return item.title;
+  }
+
+  var match = item.options.filter(function(option) {
+    return option.value === item.value;
+  });
+  var displayTitle = match.length ? match[0].text : '';
+  return displayTitle;
+}
+
+module.exports = {
+  displayTitle: displayTitle
+};
diff --git a/dist/image/index.wxml b/dist/image/index.wxml
index 53e19ef8..4724ca22 100644
--- a/dist/image/index.wxml
+++ b/dist/image/index.wxml
@@ -8,7 +8,6 @@
   <image
     wx:if="{{ !error }}"
     src="{{ src }}"
-    webp
     mode="{{ mode }}"
     lazy-load="{{ lazyLoad }}"
     class="image-class van-image__img"
diff --git a/dist/overlay/index.wxml b/dist/overlay/index.wxml
index d3e2b5f0..9212348b 100644
--- a/dist/overlay/index.wxml
+++ b/dist/overlay/index.wxml
@@ -5,4 +5,6 @@
   duration="{{ duration }}"
   bind:tap="onClick"
   catch:touchmove="noop"
-/>
+>
+  <slot></slot>
+</van-transition>
diff --git a/dist/rate/index.js b/dist/rate/index.js
index 20781e04..288ec716 100644
--- a/dist/rate/index.js
+++ b/dist/rate/index.js
@@ -8,7 +8,10 @@ VantComponent({
         readonly: Boolean,
         disabled: Boolean,
         allowHalf: Boolean,
-        size: null,
+        size: {
+            type: null,
+            observer: 'setSizeWithUnit'
+        },
         icon: {
             type: String,
             value: 'star'
@@ -44,7 +47,8 @@ VantComponent({
     },
     data: {
         innerValue: 0,
-        gutterWithUnit: undefined
+        gutterWithUnit: undefined,
+        sizeWithUnit: null
     },
     watch: {
         value(value) {
@@ -59,6 +63,11 @@ VantComponent({
                 gutterWithUnit: addUnit(val)
             });
         },
+        setSizeWithUnit(size) {
+            this.setData({
+                sizeWithUnit: addUnit(size)
+            });
+        },
         onSelect(event) {
             const { data } = this;
             const { score } = event.currentTarget.dataset;
diff --git a/dist/rate/index.wxml b/dist/rate/index.wxml
index 9d48ef79..72defd6b 100644
--- a/dist/rate/index.wxml
+++ b/dist/rate/index.wxml
@@ -12,8 +12,8 @@
   >
     <van-icon
       name="{{ index + 1 <= innerValue ? icon : voidIcon }}"
-      size="{{ size }}"
       class="van-rate__icon"
+      style="font-size :{{ size? sizeWithUnit : ''}}"
       custom-class="icon-class"
       data-score="{{ index }}"
       color="{{ disabled ? disabledColor : index + 1 <= innerValue ? color : voidColor }}"
@@ -22,9 +22,9 @@
 
     <van-icon
       wx:if="{{ allowHalf }}"
-      size="{{ size }}"
       name="{{ index + 0.5 <= innerValue ? icon : voidIcon }}"
       class="{{ utils.bem('rate__icon', ['half']) }}"
+      style="font-size :{{ size? sizeWithUnit : ''}}"
       custom-class="icon-class"
       data-score="{{ index - 0.5 }}"
       color="{{ disabled ? disabledColor : index + 0.5 <= innerValue ? color : voidColor }}"
diff --git a/dist/sidebar/index.js b/dist/sidebar/index.js
index ff6911f2..326faf5c 100644
--- a/dist/sidebar/index.js
+++ b/dist/sidebar/index.js
@@ -8,7 +8,7 @@ VantComponent({
             this.setActive(this.data.activeKey);
         },
         unlinked(target) {
-            this.items = this.children.filter((item) => item !== target);
+            this.children = this.children.filter((item) => item !== target);
             this.setActive(this.data.activeKey);
         }
     },
diff --git a/dist/stepper/index.js b/dist/stepper/index.js
index 10c2770e..c2425889 100644
--- a/dist/stepper/index.js
+++ b/dist/stepper/index.js
@@ -41,7 +41,9 @@ VantComponent({
         showMinus: {
             type: Boolean,
             value: true
-        }
+        },
+        disablePlus: Boolean,
+        disableMinus: Boolean
     },
     watch: {
         value(value) {
@@ -78,9 +80,9 @@ VantComponent({
     methods: {
         isDisabled(type) {
             if (type === 'plus') {
-                return this.data.disabled || this.data.value >= this.data.max;
+                return this.data.disabled || this.data.disablePlus || this.data.value >= this.data.max;
             }
-            return this.data.disabled || this.data.value <= this.data.min;
+            return this.data.disabled || this.data.disableMinus || this.data.value <= this.data.min;
         },
         onFocus(event) {
             this.$emit('focus', event.detail);
diff --git a/dist/stepper/index.wxml b/dist/stepper/index.wxml
index 06480dc0..456ccced 100644
--- a/dist/stepper/index.wxml
+++ b/dist/stepper/index.wxml
@@ -5,7 +5,7 @@
     wx:if="{{ showMinus }}"
     data-type="minus"
     style="{{ buttonStyle }}"
-    class="minus-class {{ utils.bem('stepper__minus', { disabled: disabled || value <= min }) }}"
+    class="minus-class {{ utils.bem('stepper__minus', { disabled: disabled || disableMinus || value <= min }) }}"
     hover-class="van-stepper__minus--hover"
     hover-stay-time="70"
     bind:tap="onTap"
@@ -27,7 +27,7 @@
     wx:if="{{ showPlus }}"
     data-type="plus"
     style="{{ buttonStyle }}"
-    class="plus-class {{ utils.bem('stepper__plus', { disabled: disabled || value >= max }) }}"
+    class="plus-class {{ utils.bem('stepper__plus', { disabled: disabled || disablePlus || value >= max }) }}"
     hover-class="van-stepper__plus--hover"
     hover-stay-time="70"
     bind:tap="onTap"
diff --git a/dist/tree-select/index.wxml b/dist/tree-select/index.wxml
index 0e8df176..d6f95a8a 100644
--- a/dist/tree-select/index.wxml
+++ b/dist/tree-select/index.wxml
@@ -6,7 +6,7 @@
   style="height: {{ innerHeight }}"
 >
   <scroll-view scroll-y class="van-tree-select__nav">
-    <van-sidebar bind:change="onClickNav" custom-class="van-tree-select__nav__inner">
+    <van-sidebar active-key="{{ mainActiveIndex }}" bind:change="onClickNav" custom-class="van-tree-select__nav__inner">
       <van-sidebar-item
         wx:for="{{ items }}"
         wx:key="index"
diff --git a/lib/dropdown-item/index.js b/lib/dropdown-item/index.js
index 06efeb68..59decdd2 100644
--- a/lib/dropdown-item/index.js
+++ b/lib/dropdown-item/index.js
@@ -8,19 +8,30 @@ component_1.VantComponent({
         type: 'ancestor',
         linked: function (target) {
             this.parent = target;
+            this.updateDataFromParent();
         },
         unlinked: function () {
             this.parent = null;
         }
     },
     props: {
-        value: null,
-        title: String,
+        value: {
+            type: null,
+            observer: 'rerender'
+        },
+        title: {
+            type: String,
+            observer: 'rerender'
+        },
         disabled: Boolean,
-        titleClass: String,
+        titleClass: {
+            type: String,
+            observer: 'rerender'
+        },
         options: {
             type: Array,
-            value: []
+            value: [],
+            observer: 'rerender'
         }
     },
     data: {
@@ -29,18 +40,24 @@ component_1.VantComponent({
         showWrapper: false,
         displayTitle: ''
     },
-    created: function () {
-        this.setData({ displayTitle: this.computedDisplayTitle(this.data.value) });
-    },
     methods: {
-        computedDisplayTitle: function (curValue) {
-            var _a = this.data, title = _a.title, options = _a.options;
-            if (title) {
-                return title;
+        rerender: function () {
+            var _this = this;
+            wx.nextTick(function () {
+                _this.parent && _this.parent.updateItemListData();
+            });
+        },
+        updateDataFromParent: function () {
+            if (this.parent) {
+                var _a = this.parent.data, overlay = _a.overlay, duration = _a.duration, activeColor = _a.activeColor, closeOnClickOverlay = _a.closeOnClickOverlay, direction = _a.direction;
+                this.setData({
+                    overlay: overlay,
+                    duration: duration,
+                    activeColor: activeColor,
+                    closeOnClickOverlay: closeOnClickOverlay,
+                    direction: direction
+                });
             }
-            var match = options.filter(function (option) { return option.value === curValue; });
-            var displayTitle = match.length ? match[0].text : '';
-            return displayTitle;
         },
         onClickOverlay: function () {
             this.toggle();
@@ -48,26 +65,47 @@ component_1.VantComponent({
         },
         onOptionTap: function (event) {
             var _this = this;
-            var _a = this.data, value = _a.value, displayTitle = _a.displayTitle;
             var option = event.currentTarget.dataset.option;
-            var optionValue = option.value;
-            if (optionValue !== value) {
-                value = optionValue;
-                displayTitle = this.computedDisplayTitle(optionValue);
-                this.$emit('change', optionValue);
-            }
-            this.setData({ showPopup: false, value: value, displayTitle: displayTitle });
-            var time = this.data.duration || 0;
+            var value = option.value;
+            var shouldEmitChange = this.data.value !== value;
+            this.setData({ showPopup: false, value: value });
             setTimeout(function () {
                 _this.setData({ showWrapper: false });
-            }, time);
-            // parent 中的 itemListData 是 children 上的数据的集合
-            // 数据的更新由 children 各自维护，但是模板的更新需要额外触发 parent 的 setData
-            this.parent.setData({ itemListData: this.parent.data.itemListData });
+            }, this.data.duration || 0);
+            this.rerender();
+            if (shouldEmitChange) {
+                this.$emit('change', value);
+            }
         },
-        toggle: function () {
-            var childIndex = this.data.childIndex;
-            this.parent.toggleItem(childIndex);
+        toggle: function (show, options) {
+            var _this = this;
+            if (options === void 0) { options = {}; }
+            var _a = this.data, showPopup = _a.showPopup, duration = _a.duration;
+            if (show == null) {
+                show = !showPopup;
+            }
+            if (show === showPopup) {
+                return;
+            }
+            if (!show) {
+                var time = options.immediate ? 0 : duration;
+                this.setData({ transition: !options.immediate, showPopup: show });
+                setTimeout(function () {
+                    _this.setData({ showWrapper: false });
+                }, time);
+                this.rerender();
+                return;
+            }
+            this.parent.getChildWrapperStyle().then(function (wrapperStyle) {
+                if (wrapperStyle === void 0) { wrapperStyle = ''; }
+                _this.setData({
+                    transition: !options.immediate,
+                    showPopup: show,
+                    wrapperStyle: wrapperStyle,
+                    showWrapper: true
+                });
+                _this.rerender();
+            });
         }
     }
 });
diff --git a/lib/dropdown-menu/index.js b/lib/dropdown-menu/index.js
index 430885f2..74f5c212 100644
--- a/lib/dropdown-menu/index.js
+++ b/lib/dropdown-menu/index.js
@@ -1,15 +1,4 @@
 "use strict";
-var __assign = (this && this.__assign) || function () {
-    __assign = Object.assign || function(t) {
-        for (var s, i = 1, n = arguments.length; i < n; i++) {
-            s = arguments[i];
-            for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
-                t[p] = s[p];
-        }
-        return t;
-    };
-    return __assign.apply(this, arguments);
-};
 Object.defineProperty(exports, "__esModule", { value: true });
 var component_1 = require("../common/component");
 var utils_1 = require("../common/utils");
@@ -20,33 +9,23 @@ component_1.VantComponent({
         name: 'dropdown-item',
         type: 'descendant',
         linked: function (target) {
-            this.children = this.children || [];
-            // 透传 props 给 dropdown-item
-            var _a = this.data, overlay = _a.overlay, duration = _a.duration, activeColor = _a.activeColor, closeOnClickOverlay = _a.closeOnClickOverlay, direction = _a.direction;
-            this.updateChildData(target, {
-                overlay: overlay,
-                duration: duration,
-                activeColor: activeColor,
-                closeOnClickOverlay: closeOnClickOverlay,
-                direction: direction,
-                childIndex: this.children.length
-            });
             this.children.push(target);
-            // 收集 dorpdown-item 的 data 挂在 data 上
-            target &&
-                this.setData({
-                    itemListData: this.data.itemListData.concat([target.data])
-                });
+            this.updateItemListData();
         },
         unlinked: function (target) {
             this.children = this.children.filter(function (child) { return child !== target; });
+            this.updateItemListData();
         }
     },
     props: {
-        activeColor: String,
+        activeColor: {
+            type: String,
+            observer: 'updateChildrenData'
+        },
         overlay: {
             type: Boolean,
-            value: true
+            value: true,
+            observer: 'updateChildrenData'
         },
         zIndex: {
             type: Number,
@@ -54,15 +33,18 @@ component_1.VantComponent({
         },
         duration: {
             type: Number,
-            value: 200
+            value: 200,
+            observer: 'updateChildrenData'
         },
         direction: {
             type: String,
-            value: 'down'
+            value: 'down',
+            observer: 'updateChildrenData'
         },
         closeOnClickOverlay: {
             type: Boolean,
-            value: true
+            value: true,
+            observer: 'updateChildrenData'
         },
         closeOnClickOutside: {
             type: Boolean,
@@ -72,7 +54,10 @@ component_1.VantComponent({
     data: {
         itemListData: []
     },
-    created: function () {
+    beforeCreate: function () {
+        var windowHeight = wx.getSystemInfoSync().windowHeight;
+        this.windowHeight = windowHeight;
+        this.children = [];
         ARRAY.push(this);
     },
     destroyed: function () {
@@ -80,67 +65,38 @@ component_1.VantComponent({
         ARRAY = ARRAY.filter(function (item) { return item !== _this; });
     },
     methods: {
-        updateChildData: function (childItem, newData, needRefreshList) {
-            if (needRefreshList === void 0) { needRefreshList = false; }
-            childItem.setData(newData);
-            if (needRefreshList) {
-                // dropdown-item data 更新，涉及到 title 的展示，触发模板更新
-                this.setData({ itemListData: this.data.itemListData });
-            }
+        updateItemListData: function () {
+            this.setData({
+                itemListData: this.children.map(function (child) { return child.data; })
+            });
+        },
+        updateChildrenData: function () {
+            this.children.forEach(function (child) {
+                child.updateDataFromParent();
+            });
         },
         toggleItem: function (active) {
-            var _this = this;
             this.children.forEach(function (item, index) {
                 var showPopup = item.data.showPopup;
                 if (index === active) {
-                    _this.toggleChildItem(item);
+                    item.toggle();
                 }
                 else if (showPopup) {
-                    _this.toggleChildItem(item, false, { immediate: true });
+                    item.toggle(false, { immediate: true });
                 }
             });
         },
-        toggleChildItem: function (childItem, show, options) {
-            var _this = this;
-            if (options === void 0) { options = {}; }
-            var _a = childItem.data, showPopup = _a.showPopup, duration = _a.duration;
-            if (show === undefined)
-                show = !showPopup;
-            if (show === showPopup) {
-                return;
-            }
-            var newChildData = { transition: !options.immediate, showPopup: show };
-            if (!show) {
-                var time = options.immediate ? 0 : duration;
-                this.updateChildData(childItem, __assign({}, newChildData), true);
-                setTimeout(function () {
-                    _this.updateChildData(childItem, { showWrapper: false }, true);
-                }, time);
-                return;
-            }
-            this.getChildWrapperStyle().then(function (wrapperStyle) {
-                if (wrapperStyle === void 0) { wrapperStyle = ''; }
-                _this.updateChildData(childItem, __assign(__assign({}, newChildData), { wrapperStyle: wrapperStyle, showWrapper: true }), true);
-            });
-        },
         close: function () {
-            var _this = this;
-            this.children.forEach(function (item) {
-                _this.toggleChildItem(item, false, { immediate: true });
+            this.children.forEach(function (child) {
+                child.toggle(false, { immediate: true });
             });
         },
         getChildWrapperStyle: function () {
-            var windowHeight = wx.getSystemInfoSync().windowHeight;
+            var _this = this;
             var _a = this.data, zIndex = _a.zIndex, direction = _a.direction;
-            var offset = 0;
             return this.getRect('.van-dropdown-menu').then(function (rect) {
                 var _a = rect.top, top = _a === void 0 ? 0 : _a, _b = rect.bottom, bottom = _b === void 0 ? 0 : _b;
-                if (direction === 'down') {
-                    offset = bottom;
-                }
-                else {
-                    offset = windowHeight - top;
-                }
+                var offset = direction === 'down' ? bottom : _this.windowHeight - top;
                 var wrapperStyle = "z-index: " + zIndex + ";";
                 if (direction === 'down') {
                     wrapperStyle += "top: " + utils_1.addUnit(offset) + ";";
@@ -148,17 +104,18 @@ component_1.VantComponent({
                 else {
                     wrapperStyle += "bottom: " + utils_1.addUnit(offset) + ";";
                 }
-                return Promise.resolve(wrapperStyle);
+                return wrapperStyle;
             });
         },
         onTitleTap: function (event) {
             var _this = this;
-            // item ---> dropdown-item
-            var _a = event.currentTarget.dataset, item = _a.item, index = _a.index;
-            if (!item.disabled) {
-                // menuItem ---> dropdown-menu
+            var index = event.currentTarget.dataset.index;
+            var child = this.children[index];
+            if (!child.data.disabled) {
                 ARRAY.forEach(function (menuItem) {
-                    if (menuItem && menuItem.data.closeOnClickOutside && menuItem !== _this) {
+                    if (menuItem &&
+                        menuItem.data.closeOnClickOutside &&
+                        menuItem !== _this) {
                         menuItem.close();
                     }
                 });
diff --git a/lib/dropdown-menu/index.wxml b/lib/dropdown-menu/index.wxml
index 22933b57..037ac3b6 100644
--- a/lib/dropdown-menu/index.wxml
+++ b/lib/dropdown-menu/index.wxml
@@ -1,10 +1,10 @@
 <wxs src="../wxs/utils.wxs" module="utils" />
+<wxs src="./index.wxs" module="computed" />
 
 <view class="van-dropdown-menu van-dropdown-menu--top-bottom">
   <view
     wx:for="{{ itemListData }}"
     wx:key="index"
-    data-item="{{ item }}"
     data-index="{{ index }}"
     class="{{ utils.bem('dropdown-menu__item', { disabled: item.disabled }) }}"
     bind:tap="onTitleTap"
@@ -14,7 +14,7 @@
       style="{{ item.showPopup ? 'color:' + activeColor : '' }}"
     >
       <view class="van-ellipsis">
-        {{item.displayTitle}}
+        {{ computed.displayTitle(item) }}
       </view>
     </view>
   </view>
diff --git a/lib/dropdown-menu/index.wxs b/lib/dropdown-menu/index.wxs
new file mode 100644
index 00000000..65388549
--- /dev/null
+++ b/lib/dropdown-menu/index.wxs
@@ -0,0 +1,16 @@
+/* eslint-disable */
+function displayTitle(item) {
+  if (item.title) {
+    return item.title;
+  }
+
+  var match = item.options.filter(function(option) {
+    return option.value === item.value;
+  });
+  var displayTitle = match.length ? match[0].text : '';
+  return displayTitle;
+}
+
+module.exports = {
+  displayTitle: displayTitle
+};
diff --git a/lib/image/index.wxml b/lib/image/index.wxml
index 53e19ef8..4724ca22 100644
--- a/lib/image/index.wxml
+++ b/lib/image/index.wxml
@@ -8,7 +8,6 @@
   <image
     wx:if="{{ !error }}"
     src="{{ src }}"
-    webp
     mode="{{ mode }}"
     lazy-load="{{ lazyLoad }}"
     class="image-class van-image__img"
diff --git a/lib/overlay/index.wxml b/lib/overlay/index.wxml
index d3e2b5f0..9212348b 100644
--- a/lib/overlay/index.wxml
+++ b/lib/overlay/index.wxml
@@ -5,4 +5,6 @@
   duration="{{ duration }}"
   bind:tap="onClick"
   catch:touchmove="noop"
-/>
+>
+  <slot></slot>
+</van-transition>
diff --git a/lib/rate/index.js b/lib/rate/index.js
index eb846fdc..1fe4c2b0 100644
--- a/lib/rate/index.js
+++ b/lib/rate/index.js
@@ -21,7 +21,10 @@ component_1.VantComponent({
         readonly: Boolean,
         disabled: Boolean,
         allowHalf: Boolean,
-        size: null,
+        size: {
+            type: null,
+            observer: 'setSizeWithUnit'
+        },
         icon: {
             type: String,
             value: 'star'
@@ -57,7 +60,8 @@ component_1.VantComponent({
     },
     data: {
         innerValue: 0,
-        gutterWithUnit: undefined
+        gutterWithUnit: undefined,
+        sizeWithUnit: null
     },
     watch: {
         value: function (value) {
@@ -72,6 +76,11 @@ component_1.VantComponent({
                 gutterWithUnit: utils_1.addUnit(val)
             });
         },
+        setSizeWithUnit: function (size) {
+            this.setData({
+                sizeWithUnit: utils_1.addUnit(size)
+            });
+        },
         onSelect: function (event) {
             var data = this.data;
             var score = event.currentTarget.dataset.score;
diff --git a/lib/rate/index.wxml b/lib/rate/index.wxml
index 9d48ef79..72defd6b 100644
--- a/lib/rate/index.wxml
+++ b/lib/rate/index.wxml
@@ -12,8 +12,8 @@
   >
     <van-icon
       name="{{ index + 1 <= innerValue ? icon : voidIcon }}"
-      size="{{ size }}"
       class="van-rate__icon"
+      style="font-size :{{ size? sizeWithUnit : ''}}"
       custom-class="icon-class"
       data-score="{{ index }}"
       color="{{ disabled ? disabledColor : index + 1 <= innerValue ? color : voidColor }}"
@@ -22,9 +22,9 @@
 
     <van-icon
       wx:if="{{ allowHalf }}"
-      size="{{ size }}"
       name="{{ index + 0.5 <= innerValue ? icon : voidIcon }}"
       class="{{ utils.bem('rate__icon', ['half']) }}"
+      style="font-size :{{ size? sizeWithUnit : ''}}"
       custom-class="icon-class"
       data-score="{{ index - 0.5 }}"
       color="{{ disabled ? disabledColor : index + 0.5 <= innerValue ? color : voidColor }}"
diff --git a/lib/sidebar/index.js b/lib/sidebar/index.js
index af537a44..f50abbff 100644
--- a/lib/sidebar/index.js
+++ b/lib/sidebar/index.js
@@ -10,7 +10,7 @@ component_1.VantComponent({
             this.setActive(this.data.activeKey);
         },
         unlinked: function (target) {
-            this.items = this.children.filter(function (item) { return item !== target; });
+            this.children = this.children.filter(function (item) { return item !== target; });
             this.setActive(this.data.activeKey);
         }
     },
diff --git a/lib/stepper/index.js b/lib/stepper/index.js
index c0c58bb4..f4e1344d 100644
--- a/lib/stepper/index.js
+++ b/lib/stepper/index.js
@@ -43,7 +43,9 @@ component_1.VantComponent({
         showMinus: {
             type: Boolean,
             value: true
-        }
+        },
+        disablePlus: Boolean,
+        disableMinus: Boolean
     },
     watch: {
         value: function (value) {
@@ -80,9 +82,9 @@ component_1.VantComponent({
     methods: {
         isDisabled: function (type) {
             if (type === 'plus') {
-                return this.data.disabled || this.data.value >= this.data.max;
+                return this.data.disabled || this.data.disablePlus || this.data.value >= this.data.max;
             }
-            return this.data.disabled || this.data.value <= this.data.min;
+            return this.data.disabled || this.data.disableMinus || this.data.value <= this.data.min;
         },
         onFocus: function (event) {
             this.$emit('focus', event.detail);
diff --git a/lib/stepper/index.wxml b/lib/stepper/index.wxml
index 06480dc0..456ccced 100644
--- a/lib/stepper/index.wxml
+++ b/lib/stepper/index.wxml
@@ -5,7 +5,7 @@
     wx:if="{{ showMinus }}"
     data-type="minus"
     style="{{ buttonStyle }}"
-    class="minus-class {{ utils.bem('stepper__minus', { disabled: disabled || value <= min }) }}"
+    class="minus-class {{ utils.bem('stepper__minus', { disabled: disabled || disableMinus || value <= min }) }}"
     hover-class="van-stepper__minus--hover"
     hover-stay-time="70"
     bind:tap="onTap"
@@ -27,7 +27,7 @@
     wx:if="{{ showPlus }}"
     data-type="plus"
     style="{{ buttonStyle }}"
-    class="plus-class {{ utils.bem('stepper__plus', { disabled: disabled || value >= max }) }}"
+    class="plus-class {{ utils.bem('stepper__plus', { disabled: disabled || disablePlus || value >= max }) }}"
     hover-class="van-stepper__plus--hover"
     hover-stay-time="70"
     bind:tap="onTap"
diff --git a/lib/tree-select/index.wxml b/lib/tree-select/index.wxml
index 0e8df176..d6f95a8a 100644
--- a/lib/tree-select/index.wxml
+++ b/lib/tree-select/index.wxml
@@ -6,7 +6,7 @@
   style="height: {{ innerHeight }}"
 >
   <scroll-view scroll-y class="van-tree-select__nav">
-    <van-sidebar bind:change="onClickNav" custom-class="van-tree-select__nav__inner">
+    <van-sidebar active-key="{{ mainActiveIndex }}" bind:change="onClickNav" custom-class="van-tree-select__nav__inner">
       <van-sidebar-item
         wx:for="{{ items }}"
         wx:key="index"