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javascriptarraystypescript

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

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]);

Solution

  • 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.