Создать функцию которая принимает массив объектов и возвращает строку

let user1 = {
  "balance": "$1,825.65",
  "picture": "https://placehold.it/32x32",
  "age": 21,
  "name": "Golden Branch",
  "gender": "male",
  "greeting": "Hello, Golden Branch! You have 7 unread messages.",
  "favouriteFruit": "banana"
};
 
let users = [user1, user2, ...]

let result = showSalary(users, age);

let user1 = {
  "balance": "$1,825.65",
  "picture": "https://placehold.it/32x32",
  "age": 21,
  "name": "Golden Branch",
  "gender": "male",
  "greeting": "Hello, Golden Branch! You have 7 unread messages.",
  "favouriteFruit": "banana"
};
let user2 = {
  "balance": "$22,666.33",
  "picture": "https://placehold.it/32x32",
  "age": 21,
  "name": "Frank Hell",
  "gender": "male",
  "greeting": "Hello, Golden Branch! You have 7 unread messages.",
  "favouriteFruit": "banana"
};
 
let user3 = {
  "balance": "$5,999.65",
  "picture": "https://placehold.it/32x32",
  "age": 21,
  "name": "George Bush",
  "gender": "male",
  "greeting": "Hello, Golden Branch! You have 7 unread messages.",
  "favouriteFruit": "banana"
};
 
let users = [user1, user2, user3];
 
const result = (() => users.map((u) => u['name'] + ': ' + u['balance']).join(', '))();
 
console.log(result);// Golden Branch: $1,825.65, Frank Hell: $22,666.33, George Bush: $5,999.65

let users = [user1, user2, user3];
const maxAge = 21;
const result = ((users, age) =>
  users
    .filter((u) => u.age <= age)
    .map((u) => u["name"] + ": " + u["balance"])
    .join(", "))(users, maxAge);

function showSalary(users, age) {
  let result = [];
  users.forEach(function(item) {
    if (item.age <= age){
      result.push(`${item.name}, ${item.balance}`);
    }
  });
 
  return result.join('\n');
}

const showSalary = (users, age) => users.filter((u) => u['age'] <= age).map((u) => u['name'] + ': ' + u['balance']).join("\n");
console.log(showSalary(users, 21));
 
// Golden Branch: $1,825.65
// George Bush: $5,999.65

const res = (usr, ag) => usr.reduce((a, b) => a += b.age <= ag ? b.name + ': ' + b.balance+'\n' : '', '');

function showSalary(users, age) {
  let result = '';
  for (user of users) {
    if (user.age <= 21) result += `${user.name}: ${user.balance}\n`; 
  }
  return result.trim(); // Можно без trim
}
console.log(showSalary(users, 21));