Get an error when I call object's properties in Array

Question

In typescript code I have an array with objects in it. When I call \"getUsers(users)\" function, it returns the result as I need, but in console I get this error \"Uncaught Type

Answer 1

The issue is with i <= users.length , it need to be i < users.length.i++ will increment the value of i by 1 but the length is three and the index start from 0 so the elements are occupied till second index, hence i <= users.length will actually try to access the element in the third index which is unefined

let users = [{
    firstName: "John",
    lastName: "Doe",
    age: 34
  },
  {
    firstName: "Jack",
    lastName: "Jackson",
    age: 23
  },
  {
    firstName: "Ann",
    lastName: "Watson",
    age: 24
  }
];

function getUsers(users) {
  for (var i = 0; i < users.length; i++) {
    console.log(users[i].firstName + " is " + users[i].age + " years old!");
  }
}
getUsers(users);