processList-shiftSmallandMerge.md

let firstList = [4, 6, 8, 9]
let secondList = [2, 3, 5, 7]

function getSmallestThenRemove(firstList, secondList) {
    let smallestFirstList = firstList[0];
    let smallestSecondList = secondList[0];

    if (smallestFirstList < smallestSecondList) {
        return firstList.shift()
    } else {
        return secondList.shift()
    }
}

function mergeLists(firstList, secondList) {
    let newList = [];
    let iteratedNum;

    while (firstList.length != 0 && secondList.length != 0) {
        let iteratedNum = getSmallestThenRemove(firstList, secondList)
        newList.push(iteratedNum)
    }
    return newList.concat(firstList).concat(secondList)
}

console.log(mergeLists(firstList, secondList));