validate objects in array javascript code example

Example 1: javascript check if value exists in array of objects

var arr = [{ id: 1, name: 'JOHN' }, 
  { id: 2, name: 'JENNIE'}, 
  { id: 3, name: 'JENNAH' }];

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

console.log(userExists('JOHN')); // true
console.log(userExists('JUMBO')); // false

Example 2: check object in array javascript

var obj = {a: 5};
var array = [obj, "string", 5]; // Must be same object
array.indexOf(obj) !== -1 // True