一維數組元素分類轉換成二維數組

數組元素按照某個key分類轉換成二維數組

  let test =[
        {id:0,code:"4"},
        {id:1,code:"1"},
        {id:2,code:"1"},
        {id:3,code:"2"},
        {id:4,code:"2"},
        {id:5,code:"3"},
        {id:6,code:"4"},
        {id:7,code:"1"},
        {id:8,code:"5"},

    ];
    function classify(arr,key) {
        let obj = {};
        arr.forEach((e)=>{
            if(typeof obj[e[key]]=='undefined'){
                obj[e[key]] = []
            }
            obj[e[key]].push(e)
        });
        return Object.values(obj)
    }

  console.log(classify(test,"code"))

效果圖：