Array of object - get id for selected user name inside function

Question

const user = [
{name:"jonh" ,id:EAD1234},
{name:"peter" ,id:EAD1235},
{name:"matt" ,id:EAD1236},
{name:"henry" ,id:EAD1237},
]

I have above mentioned array of object, I want to get selected user id dynamically based on user selection using es6 and javascript eg if i select john i should get EAD1234. and it must suitable on large number of records

I tried using filter method

Answer 1

No need to filter through the whole array if the id values are unique:

function getUserByID(id, users) {
  for (const u of users) {
    if (u.id === id) {
      return u;
    }
  }
  return null;
}

If your data really is exceptionally large and it makes sense to store it on the front-end look into using IndexedDB .

---

Edit : Someone in the comments somewhere mentioned Array.prototype.find() , so you might as well just use the built-in.

function getUserByID(id, users) {
  return users.find((u) => u.id === id) || null;
}

Answer 2

If the data is samll,then just combine Array.filter() and Array.map() can do it.

If the data is too large,we can store the data into a database such as mysql or redis ,then query it dynamiclly

 const user = [ {name:"jonh",id:'EAD1234'}, {name:"peter",id:'EAD1235'}, {name:"matt",id:'EAD1236'}, {name:"henry",id:'EAD1237'} ] let id = 'EAD1234' let result = user.filter(u => u.id === id).map(u => u.name) console.log(result)

Answer 3

const user = [
    {name:"john"  ,id:'EAD1234'},
    {name:"peter" ,id:'EAD1235'},
    {name:"matt"  ,id:'EAD1236'},
    {name:"henry" ,id:'EAD1237'},
];

let userName = "john";
let userId = user.filter(user => user.name === userName)[0].name;