SOURCE

var relationCase = [

          {
            relationId: "1f72675b-2d63-4815-a918-c219d623fb83",
            relation_applicationCode: "S-00005001-0001",
            relation: "1",
            fraudStrtus: "NEW",
            esRule: [],
                                                      
            broadcastUrl: "http://10.10.39.61/fac/api/anayzeCase/update",
            color: "#efef2ff2",
            tenantID: "novaB"
          },{
            relationId: "80b8269d-1a4f-444b-afa9-e5e5f128d6db",
            relation_applicationCode: "S-00005001-0001003",
            relation: "1",
            fraudStrtus: "NEW",
            esRule: [
              
            ],
            broadcastUrl: "http://10.10.39.61/fac/api/anayzeCase/update",
            color: "#95ff95",
            tenantID: "novaB"
          },{
           relationId: "feafe8fd-71434b80a2a",
            relation_applicationCode: "S-1223340",
            relation: "3",
            fraudStrtus: "FRAUD",
            esRule: [
              
            ],
            broadcastUrl: "http://10.10.39.61/fac/api/anayzeCase/update",
            color: "#95ff95",
            tenantID: "BankA"
          }
        ];

function group(arr) {
    var obj = {};
    if (Array.isArray(arr)) {
        for (var i = 0; i < arr.length; ++i) {
            // 获取每一个relation
            var relation = arr[i].relation;
            if (relation in obj) obj[relation].push(arr[i]);
            else obj[relation] = [arr[i]];
        }
    }
    return obj;
}

function max(obj) {
    var ret = 0;
    if (obj && typeof obj === "object") {
        for (var key in obj) {
            var length = obj[key].length;
            if (length > ret) ret = length;
        }
    }
    return ret;
}



const data = group(relationCase)

var arr = []
for (let i in data) {
    let o = {};
    o[i] = data[i]; //即添加了key值也赋了value值 o[i] 相当于o.name 此时i为变量
    arr.push(o)
}
console.log(arr);