How to find first non null value in a typescript array?

Question

I have an arr variable which looks as below:

const arr = [undefined, undefined, 'hello', 'hello', 'hi'];

I want to print out the first non-null value from within the arr array variable.

In above array, the output should be hello

I have written following logic but it is not giving the correct result:

const arr = [undefined, undefined, 'hello', 'hello', 'hi'];
const index = arr.length;

while (index-- && !arr[index]);

console.log(arr[index]);

Answer 1

Just use find:

const arr = [undefined, undefined, 'hello', 'hello', 'hi'];

console.log(arr.find(el => el !== undefined))

It returns the value of the first element in the provided array that satisfies the provided testing function.

Answer 2

const arr = [undefined, null, 'hello', 'hello', 'hi'];

console.log(arr.find(el => el))
// or
console.log(arr.find(el => !!el))