getNestedItemAtPath.js

const x = {
    a:{
        b:{
            c:'neat'
        }
    }
}

const loop = (object, path) => {
    let index = 0
    let cur = object

    while (index < path.length){
        cur = cur[path[index]]
        index++
    }

    return cur
}

console.log(loop(x, ['a','b','c']))

getNestedItemAtPathUpdated.js

const x = {
    a:{
        b:{
            c:'neat'
        }
    }
}

const loop = (object, path) => {
    path = path.reverse()
    let cur = object

    while (path.length > 0){
        cur = cur[path.pop()]
    }

    return cur
}

console.log(loop(x, ['a','b','c']))