find returns the first item that satisfies the condition in the callback. You are returning b, which is the index. The returned result is the second item since the first item's index is 0, which is falsy. The second index is 1, which is truthy.

The find() method returns the value of the first element in the provided array that satisfies the provided testing function. If no values satisfy the testing function, undefined is returned.

const array1 = [5, 12, 8, 130, 44];

const found = array1.find(n=>n>20); console.log(found);

this will return 130 because n is greater than 20 we specified here

const array1 = [3,4,5,8,1]

const found = array1.find(n=>n>3)

will return 4

this will be correct one

const array1 = [12,5,8, 130, 44];

var check=array1.find(b => b>10 ); console.log(check);

and the error is because you are not targeting the correct element

The find() method returns the value of the first element in the provided array that satisfies the provided testing function. If no values satisfy the testing function, undefined is returned.