expand-row-keys=expandKeys

This is a Vue.js directive that is used to expand specific rows in a table using an array of keys. The 'expandKeys' variable is an array that contains the keys of the rows that need to be expanded.

Here is an example of how this directive can be used:

<template>
  <div>
    <table>
      <thead>
        <tr>
          <th>Name</th>
          <th>Age</th>
        </tr>
      </thead>
      <tbody>
        <tr v-for="person in people" :key="person.id" :expand-row-keys="expandKeys">
          <td>{{ person.name }}</td>
          <td>{{ person.age }}</td>
        </tr>
      </tbody>
    </table>
  </div>
</template>

<script>
export default {
  data() {
    return {
      people: [
        { id: 1, name: 'John', age: 30 },
        { id: 2, name: 'Jane', age: 25 },
        { id: 3, name: 'Bob', age: 40 },
        { id: 4, name: 'Sue', age: 35 },
      ],
      expandKeys: [2, 4], // Expand rows with key 2 and 4
    };
  },
};
</script>

In this example, the 'expand-row-keys' directive is added to the 'tr' element inside the 'v-for' loop. The 'expandKeys' array contains the keys of the rows that need to be expanded, which are rows with keys 2 and 4. When the table is rendered, only the rows with keys 2 and 4 will be expanded.