vue-搜索功能-實時監聽搜索框的輸入，N毫秒請求一次數據

<template>
  <div class="search-box">
    <input class="box"
           :placeholder="placeholder"
           v-model="query"
    >
  </div>
</template>
<script type="text/ecmascript-6">
  import { debounce } from 'common/js/util'
 
  export default {
    props: {
      placeholder: {
        type: String,
        default: '搜索歌曲、歌手'
      }
    },
    data() {
      return {
        query: ''
      }
    },
    created() {
      this.$watch('query', debounce((newQuery) => {
        this.$emit('query', newQuery)
      }, 200))
    }
  }
</script>

export function debounce(func, delay) {
  let timer;
  return function (...args) {
    if (timer) {
      clearTimeout(timer)
    }
    timer = setTimeout(() => {
      func.apply(this, args)
    }, delay)
  }
}