如何在Vuejs/Javascript中使过滤器不区分大小写

Vue.filter('caseInsensitiveFilter', function(value, keyword) {
  if (!value) return '';
  if (!keyword) return value;

  keyword = keyword.toLowerCase();

  return value.filter(function(item) {
    return item.toLowerCase().indexOf(keyword) !== -1;
  });
});

<template>
  <div>
    <input v-model="searchKeyword" placeholder="Search">
    <ul>
      <li v-for="item in filteredItems">{{ item }}</li>
    </ul>
  </div>
</template>

<script>
export default {
  data() {
    return {
      searchKeyword: '',
      items: ['Apple', 'Banana', 'Orange', 'Grape']
    };
  },
  computed: {
    filteredItems() {
      return this.items.filter(item => {
        return item | caseInsensitiveFilter(this.searchKeyword);
      });
    }
  }
};
</script>