情景:項目中用到，ElementUI el-table中選擇指定項并且刪除，順便記錄下

增刪操作

兩個數組對象去重 實例：

        let arr = [{id: 1, name: 'AAA'}, {id: 2, name: 'BBB'}, {id: 3, name: 'CCC'}, {id: 4, name: 'DDD'}]
        let arr2 = [{id: 2, name: 'BBB'}, {id: 3, name: 'CCC'}]
        let newArr = []

        arr2.forEach(item => {
          newArr.push(item.id)
        })
        for (let id of newArr) {
          arr = arr.filter(item => {
            return id !== item.id
          })
        }
       console.log(arr)
       //得到[{id: 1, name: 'AAA'}, {id: 4, name: 'DDD'}]

向數組中添加對象，防止重復

let arr =[{id: 1, name: 'AAA'}, {id: 2, name: 'BBB'}, {id: 3, name: 'CCC'}, {id: 4, name: 'DDD'}]
let arr2 = {id:4,name:'DDD'}
//向arr中添加arr2 假如存在，就不添加
arr = arr.filter(item=>item.id!=4)
arr.push(arr2)
console.log(arr)
//[{id: 1, name: 'AAA'}, {id: 2, name: 'BBB'}, {id: 3, name: 'CCC'}, {id: 4, name: 'DDD'}]