js数组的转变

js数组去重

   var data = [
        {'name' : '张三'},
        {'name' : '李四'},
        {'name' : '张刘'},
        {'name' : '张三'}
    ];
    //js数组去重
    var obj = {};
    var res = [];
    for (var i = 0; i < data.length; i++) {
       if(!obj[data[i].name]){
        obj[data[i].name] = 1;
        res.push( data[i].name);
       }
    }
    // console.log(res);

js分组求和，根据name和month分组

    //js分组求和，根据name和month分组
    var data = [
        {'month' : '201903','name' : '张三','num' : 5},
        {'month' : '201904','name' : '李四','num' : 5},
        {'month' : '201905','name' : '张三','num' : 6},
        {'month' : '201903','name' : '张三','num' : 6}, 
        {'month' : '201903','name' : '张三','num' : 6},
        {'month' : '201904','name' : '李白','num' : 6},
        {'month' : '201903','name' : '张三','num' : 6}
    ];
    var obj = {};
    var res = [];
    for (var i = 0; i < data.length; i++) {
       if(!obj[data[i].name] || !obj[data[i].month]){
        obj[data[i].name] = 1;
        obj[data[i].month] = 2;
        res.push({
            name :data[i].name,
            month :data[i].month,
            num : data[i].num,
        });
       }else{
            var num = 0;
            for (var j = 0; j< res.length; j++) {
               if(res[j].month == data[i].month && res[j].name == data[i].name){
                    num = parseFloat(res[j].num)+parseFloat(data[i].num);
                    res[j].num = num;

               }
            }
       }
    }
console.log(res);

js去重：

var arr = [
    {"id":"1001","name":"值1","value":"111"},
    {"id":"1001","name":"值1","value":"11111"},
    {"id":"1002","name":"值2","value":"25462"},
    {"id":"1002","name":"值2","value":"23131"},
    {"id":"1002","name":"值2","value":"2315432"},
    {"id":"1003","name":"值3","value":"333333"}
];
 
var map = {};
    dest = [];
for(var i = 0; i < arr.length; i++){
    var ai = arr[i];
    if(!map[ai.id]){
        dest.push({
            id: ai.id,
            name: ai.name,
            data: [ai]
        });
        map[ai.id] = ai;
    }else{
        for(var j = 0; j < dest.length; j++){
            var dj = dest[j];
            if(dj.id == ai.id){
                dj.data.push(ai);
                break;
            }
        }
    }
}