[bugfix] Area: error when list empty (#661)

example/pages/area/index.js

@@ -1,11 +1,24 @@
 import Page from '../../common/page';
-import AreaList from './area';
 
 Page({
   data: {
-    areaList: AreaList,
+    areaList: {},
+    loading: true,
     value: 330302
   },
+
+  onShow() {
+    wx.request({
+      url: 'https://cashier.youzan.com/pay/wsctrade/order/buy/getAllRegion.json',
+      success: response => {
+        this.setData({
+          loading: false,
+          areaList: response.data.data
+        });
+      }
+    });
+  },
+
   onChange(event) {
     console.log(event);
   }

example/pages/area/index.wxml

@@ -1,11 +1,25 @@
 <demo-block title="基础用法">
-  <van-area area-list="{{ areaList }}" />
+  <van-area
+    loading="{{ loading }}"
+    area-list="{{ areaList }}"
+  />
 </demo-block>
 
 <demo-block title="选中省市县">
-  <van-area area-list="{{ areaList }}" value="{{ value }}" />
+  <van-area
+    value="{{ value }}"
+    loading="{{ loading }}"
+    area-list="{{ areaList }}"
+  />
 </demo-block>
 
 <demo-block title="配置显示列">
-  <van-area area-list="{{ areaList }}" columns-num="{{ 2 }}" title="标题" bind:confirm="onChange" bind:change="onChange" />
+  <van-area
+    title="标题"
+    columns-num="{{ 2 }}"
+    loading="{{ loading }}"
+    area-list="{{ areaList }}"
+    bind:change="onChange"
+    bind:confirm="onChange"
+  />
 </demo-block>

packages/area/index.ts

@@ -68,13 +68,13 @@ VantComponent({
       const { value } = event.detail;
       const { pickerValue, displayColumns } = this.data;
       const index = pickerValue.findIndex((item, index) => item !== value[index]);
+      const values = displayColumns[index];
+
       // 没有变更 或 选中项序号小于0 不处理
-      if (index < 0 || value[index] < 0) {
+      if (!value[index] || !values[value[index]]) {
         return;
       }
 
-      const values = displayColumns[index];
-
       this.code = values[value[index]].code;
       this.setValues();
       this.$emit('change', {
@@ -118,7 +118,7 @@ VantComponent({
     },
 
     setValues() {
-      let code = this.code || Object.keys(this.data.areaList.county_list)[0] || '';
+      let code = this.code || Object.keys(this.data.areaList.county_list || {})[0] || '';
       const province = this.getList('province');
       const city = this.getList('city', code.slice(0, 2));