feat:add tree demo

src/views/tree/index.vue

@@ -0,0 +1,71 @@
+<template>
+  <div class="app-container">
+    <el-input placeholder="Filter keyword" v-model="filterText" style="margin-bottom:30px;"></el-input>
+
+    <el-tree class="filter-tree" :data="data2" :props="defaultProps" default-expand-all :filter-node-method="filterNode" ref="tree2"></el-tree>
+
+  </div>
+</template>
+
+<script>
+export default {
+  watch: {
+    filterText(val) {
+      this.$refs.tree2.filter(val)
+    }
+  },
+
+  methods: {
+    filterNode(value, data) {
+      if (!value) return true
+      return data.label.indexOf(value) !== -1
+    }
+  },
+
+  data() {
+    return {
+      filterText: '',
+      data2: [{
+        id: 1,
+        label: 'Level one 1',
+        children: [{
+          id: 4,
+          label: 'Level two 1-1',
+          children: [{
+            id: 9,
+            label: 'Level three 1-1-1'
+          }, {
+            id: 10,
+            label: 'Level three 1-1-2'
+          }]
+        }]
+      }, {
+        id: 2,
+        label: 'Level one 2',
+        children: [{
+          id: 5,
+          label: 'Level two 2-1'
+        }, {
+          id: 6,
+          label: 'Level two 2-2'
+        }]
+      }, {
+        id: 3,
+        label: 'Level one 3',
+        children: [{
+          id: 7,
+          label: 'Level two 3-1'
+        }, {
+          id: 8,
+          label: 'Level two 3-2'
+        }]
+      }],
+      defaultProps: {
+        children: 'children',
+        label: 'label'
+      }
+    }
+  }
+}
+</script>
+