Vue3 Element Tree Table Lazy Load Node Refresh Issue Solution

Introduction

Tree tables are commonly employed to display hierarchical data structures in a user-friendly and organized manner. In Vue3, the Element UI library offers a robust tree table component that supports lazy loading, a technique that optimizes performance by fetching data only when necessary. However, certain scenarios may arise where refreshing individual nodes in the tree table proves challenging. This article aims to shed light on this issue and present an effective solution.

Understanding Lazy Loading

Lazy loading is a strategy for fetching data only when it is needed. In the context of tree tables, this means that child nodes are not loaded initially. Instead, they are loaded dynamically when the user expands the parent node. This approach enhances performance by reducing the amount of data that needs to be loaded upfront.

Issue: Node Refresh

A common challenge encountered when working with tree tables is the inability to refresh individual nodes without reloading the entire table. This limitation can hinder the user experience and make it difficult to maintain dynamic data.

Solution: Dynamic Node Update

To address this issue, we will utilize the dynamic node update capability provided by the Element UI tree table component. This approach allows us to selectively update individual nodes without affecting the rest of the table. Here's how to achieve this:

1. Identify the Node to Update:

Determine the specific node that requires updating. This can be accomplished by obtaining the node's unique identifier, such as its ID or key.

2. Fetch Updated Data:

Retrieve the updated data for the identified node from the server or appropriate data source.

3. Update the Node:

Use the updateNode method provided by the Element UI tree table component to update the node with the new data. This method takes two arguments:

• Node to Update: The node that needs to be updated.
• Updated Data: The new data to replace the existing data in the node.

Code Example

The following code snippet demonstrates how to dynamically update a node in a Vue3 Element tree table:

<template>
  <el-tree-table
    :data="tableData"
    :lazy="true"
    @node-expand="handleNodeExpand"
  >
    <el-table-column prop="name" label="Name" />
    <el-table-column prop="age" label="Age" />
  </el-tree-table>
</template>

<script>
import { ref } from 'vue'
import { updateNode } from 'element-plus/lib/components/tree-table/src/util'

export default {
  setup() {
    const tableData = ref([
      {
        id: 1,
        name: 'John Doe',
        age: 30,
        children: [
          {
            id: 2,
            name: 'Jane Smith',
            age: 25,
          },
        ],
      },
    ])

    const handleNodeExpand = (row, node, instance) => {
      if (node.children && node.children.length > 0) {
        return
      }

      const nodeId = row.id
      fetch(`api/nodes/${nodeId}`)
        .then(res => res.json())
        .then(data => {
          // Update the node with the new data
          updateNode(instance, row, data)
        })
    }

    return {
      tableData,
      handleNodeExpand,
    }
  },
}
</script>

Conclusion

By harnessing the power of dynamic node updates in Vue3 Element tree tables, we can overcome the limitations of lazy loading and achieve a more flexible and responsive user interface. This technique enables us to selectively refresh individual nodes without compromising the overall performance of the table.