let arr1 = [{id:1,name:'bj'},{id:2,name:'sh'}];

let arr2 = [{id:3,name:'bj'},{id:2,name:'sh'},{id:4,name:'nj'}];

let arr = arr1.concat(arr2);

let map = new Map();

for (let i = 0, len = arr.length; i < len; i++) {

if (!map.has(arr[i].id)) {

map.set(arr[i].id, arr[i]);

} else {

let t = map.get(arr[i].id);

t.common = ['1', '1'];

map.set(arr[i].id, t);

}

}

let result = Array.from(map.values());

console.dir(result);