[new feature] List 考虑错误情况，增加 error-text 属性 #2567 (#2568)

packages/list/en-US.md

@@ -16,7 +16,9 @@ Vue.use(List);
 <van-list
   v-model="loading"
   :finished="finished"
+  :error.sync="error"
   finished-text="Finished"
+  error-text="Request failed. Click to reload..."
   @load="onLoad"
 >
   <van-cell
@@ -34,6 +36,7 @@ export default {
       list: [],
       loading: false,
       finished: false
+      error: false
     };
   },
 
@@ -45,6 +48,9 @@ export default {
         }
         this.loading = false;
 
+        // when error loaded:
+        // this.error = true;
+
         if (this.list.length >= 40) {
           this.finished = true;
         }
@@ -60,9 +66,11 @@ export default {
 |------|------|------|------|
 | loading | Whether to show loading info，the `load` event will not be triggered when loading | `Boolean` | `false` |
 | finished | Whether loading is finished，the `load` event will not be triggered when finished | `Boolean` | `false` |
+| error | Whether loading is error，the `load` event will be triggered only when error text clicked, the `sync` modifier is needed | `Boolean` | `false` |
 | offset | The load event will be triggered when the distance between the scrollbar and the bottom is less than offset | `Number` | `300` |
 | loading-text | Loading text | `String` | `Loading...` |
 | finished-text | Finished text | `String` | - |
+| error-text | Error loaded text | `String` | - |
 | immediate-check | Whether to check loading position immediately after mounted | `Boolean` | `true` |
 
 ### Event