24 - 激活的样式-指令

[cone41]

<script setup lang="ts">
import { ref, watchEffect } from 'vue';

/**
 * Implement the custom directive
 * Make sure the list item text color changes to red when the `toggleTab` is toggled
 *
 */
const VActiveStyle = {
  mounted(el, binding) {
    const [style, fn] = binding.value;
    watchEffect(() => {
      const flag = fn();
      Object.keys(style).forEach((key) => {
        el.style[key] = flag ? style[key] : '';
      });
    });
  },
};

const list = [1, 2, 3, 4, 5, 6, 7, 8];
const activeTab = ref(0);
function toggleTab(index: number) {
  activeTab.value = index;
}
</script>

<template>
  <ul>
    <li
      v-for="(item, index) in list"
      :key="index"
      v-active-style="[{ color: 'red' }, () => activeTab === index]"
      @click="toggleTab(index)"
    >
      {{ item }}
    </li>
  </ul>
</template>