搜索选择框 过滤数据

// 搜索过滤 val:传入值, list:列表数组, key:对比字段, filterIndex:过滤开始的索引
export function dataFilter(val, list, key, filterIndex) {
  filterIndex = filterIndex >= 0 ? filterIndex : 0
  if (val != '') {
    const or = /[A-Za-z]+$/
    const arr = list
    let searchKey = val
    if (or.test(searchKey)) {
      searchKey = searchKey.toUpperCase()
    }
    searchKey = searchKey.toString()
    const len = searchKey.length
    let isTopFilter = false
    const allFilterList = []
    const newList = arr.filter((item) => {
      let items = item[key]
      if (or.test(items)) {
        items = items.toUpperCase()
      }
      for (let index = 0; index < items.length; index++) { // 全局过滤
        let newItems = items
        newItems = newItems.substring(index, index + len)
        if (newItems == searchKey) {
          allFilterList.push(item)
        }
      }
      if (filterIndex >= 0) { // 开头过滤
        items = items.toString().substring(filterIndex, filterIndex + len)
        if (items == searchKey) {
          isTopFilter = true
          return item
        }
      }
    })
    if (!isTopFilter) {
      return allFilterList
    }
    return newList
  } else {
    // val不存在还原数组
    return list
  }
}