A Technical test from CitrusByte

citrusbyte.test.js

const flattenArray = (initialArray, depth = (1/0), result = []) => {  
    if(initialArray == null){
        return result;
    } 

    for(const item of initialArray){
        if(depth > 1 && Array.isArray(item)){
            flattenArray(item, depth - 1, result);
        } else {
            result.push(item);
        }
    }

    return result;
}

const input = [[1,2,[3]],4]; 
console.log(flattenArray(input)); // should return [1,2,3,4]