flatten array

flattenArray.js

function flattenArray(inputArray, outputArray = []) {
    for (let i = 0; i < inputArray.length; i++) {
        const element = inputArray[i];
        if (typeof element === "object" && element.length > 0) {
            flattenArray(element, outputArray)
            continue;
        }
        outputArray.push(element);
    }
    return outputArray;
}

var test = [1,2,[5],[[6]],3,4];
console.log(flattenArray(test));