How to convert string to Words array in javascript?

I am trying to convert "getuserdetailsbyname" to ["get","user","details","by","name"] in short I am trying to convert the all small written varibale names to camel case. And so far I have not found a solution that could detect it and convert this to uppercase. With a words array I am able to convert "getuserdetailsbyname" to ["get","user","detail"] and the remaining array get discarded.Here is my code

import { words } from "popular-english-words";
import { splitIntoWords } from "@zzzzbov/split-into-words";
const word = words.getAll();

console.log("ALlWords", word);
// console.log("SplitIntoWords",splitIntoWords("getuserdetailsbytrim"))

function toUpperCase(compiledArray) {
   for (let counter = 0; counter < compiledArray.length; counter++) {
      if (counter != 0) {
         compiledArray[counter] =
         compiledArray[counter].charAt(0).toUpperCase() +
         compiledArray[counter].slice(1);
       }
   }
   return compiledArray;
 }
 function convertVariable(variableName) {
 let compiledArray = [];
 const bool = false;
 for (let counter = 0; counter < variableName.length; counter++) {
   if (counter > 2) {
     if (word.includes(variableName.slice(0, counter))) {
        console.log(variableName.slice(0, counter));
        compiledArray.push(variableName.slice(0, counter));
        variableName = variableName.slice(counter);
     }
  }
}

 console.log("compiledArr", compiledArray);
}
convertVariable("getuserdetailbytrim");
convertVariable("getuserdetailedSubscriptions");

console.log(
  "toUpperCase",
   toUpperCase(["get", "user", "details", "from", "trim"])
);