Fibonacci secence in javascript explained code example

Example 1: javascript fibonacci

function fibonacci(n) {
   return n < 1 ? 0
        : n <= 2 ? 1
        : fibonacci(n - 1) + fibonacci(n - 2);
}

console.log(fibonacci(4));

Example 2: fibonacci sums javascript

// Implement a method that finds the sum of the first n
// fibonacci numbers recursively. Assume n > 0

function fibsSum(n) {
    if ( n === 1 ) {
        return 1;
    }
    if (n === 2 ) {
        return 2;
    }
    let sum = fibsSum(n-1) + n;
    return sum;
}