JSFiddle - React, Tailwind, and code Playground

JavaScript

function stringToObj(path, obj) {
  var parts = path.split(".");
  var part;
  while ((part = parts.shift())) {
    if (typeof obj[part] != "object") obj[part] = {};
    obj = obj[part]; // line 6
  }
}

let result = {};
stringToObj("a.b.c", result);
console.log(result); // outputs the json