find array in nested array of objects

Question

I want to find an array inside a nested array of objects, how can I do that?

Here is my array

const arr = [
 {
 "teamA": [
 {
 "_id": "5fcb57c5a1a426c03bcfd25f",
 "level": 10,
 "username": "asaf"
 }
 ],
 "teamB": [],
 "options": {}
 },
 {
 "teamA": [
 {
 "_id": "a7fgy3h1uio",
 "level": 10,
 "username": "asaf"
 }
 ],
 "teamB": [
 {
 "_id": "13rfedsc32",
 "level": 10,
 "username": "asaf"
 },
 {
 "_id": "dghg453r3q",
 "level": 10,
 "username": "asaf"
 }
 ],
 "options": {}
 }
];

now I want to create a function that returns me the array of the team that a player is in by the _id

for example, I created this:

const findTeam = playerId => {
 const match = arr.find(({ teamA, teamB }) => [teamA, teamB].some(team => team.some(i => i._id == playerId)));
 if(!match) return;
 const { teamA, teamB } = match;
 const team = [teamA, teamB].find(team => team.some(i => i._id == playerId));
 return team;
};

and it's working, but the way I did it looks very messy, there is any neat way to do that? Thanks!

• michael: does every object of array has only two teams - teamA & teamB?
• Asaf: @baymax yes correct

Answer 1

You can use flatMap:

const arr = [{teamA:[{_id:"5fcb57c5a1a426c03bcfd25f",level:10,username:"asaf"}],teamB:[],options:{}},{teamA:[{_id:"a7fgy3h1uio",level:10,username:"asaf"}],teamB:[{_id:"13rfedsc32",level:10,username:"asaf"},{_id:"dghg453r3q",level:10,username:"asaf"}],options:{}}];
const findTeam = playerId => arr.flatMap(({ teamA, teamB }) => [teamA, teamB])
 .find(team => team.some(player => player._id === playerId));
console.log(findTeam('13rfedsc32'));

Explanation:

arr.flatMap(({ teamA, teamB }) => [teamA, teamB]) will return an Array of all teams from all matches, regardless of them being A or B. You can then easily find the one which contains the wanted player.