JSFiddle - React, Tailwind, and code Playground

JavaScript

var source = [];
source['lvl1'] = [];
source['lvl1']['lvl2a'] = [];
source['lvl1']['lvl2a']['lvl3'] = "ping";
source['lvl1']['lvl2b'] = "pong";

function logSource(path) {
    var sourceValue = source[path[0]];
    for (var i = 1; i < path.length; i++) {
        sourceValue = sourceValue[path[i]];
    }
    console.log(sourceValue);
}

var path1 = ["lvl1","lvl2a","lvl3"];
var path2 = ["lvl1","lvl2b"];

logSource(path1);
logSource(path2);