javascript check if value in object array using map code example

Example 1: how to check if an element exists in an array of objects js

var arr = [{ id: 1, username: 'fred' }, 
  { id: 2, username: 'bill'}, 
  { id: 3, username: 'ted' }];

function userExists(username) {
  return arr.some(function(el) {
    return el.username === username;
  }); 
}

console.log(userExists('fred')); // true
console.log(userExists('bred')); // false

Example 2: how to Check if an array contains an object in javascript

// To check if an array contains an Object

const myArrayObj = [{
    'username': 'Player 1',
    'email': '[email protected]'
}, {
    'username': 'Player 2',
    'email': '[email protected]'
}];

// Create a helper function to compear the objects
const isEqual = (first, second) => {
    return JSON.stringify(first) === JSON.stringify(second);
}

const result = myArrayObj.some(e => isEqual(e, {
    'username': 'Player 1',
    'email': '[email protected]'
}));

console.log(result); // true