next increasing values (not working).js

function nextIncreasingValues(array) {
    let nivs = [];
    
    for (let i = array.length - 1; i >= 0; i--) {
        let currentNumber = array[i];
        let niv;
        
        if (i === array.length - 1) {
            // the last element always has a NIV of -1
            niv = -1;
        } else {
            let nextNumber = array[i + 1];
            let nextNumbersNiv = nivs[i + 1];
            
            if (nextNumber > currentNumber) {
                // the next number is bigger, so that's the niv
                niv = nextNumber;
            } else if (nextNumbersNiv > currentNumber) {
                // the next number is not bigger but has a niv that's bigger, so that's the niv
                niv = nextNumbersNiv;
            } else {
                // the next number is smaller and so is its niv, so there is no niv
                niv = -1;
            }
        }
        
        nivs[i] = niv;
    }
    
    return nivs;
}

// test

let numbers = [4, 3, 4, 5];
let expectedNivs = [5, 4, 5, -1];

let nivs = nextIncreasingValues(numbers);

console.log(expectedNivs); // [ 5, 4, 5, -1 ]
console.log(nivs);         // [ -1, 4, 5, -1 ]