JSFiddle - React, Tailwind, and code Playground

HTML

<input type="file" id="file-input" />
<h3>Contents of parshed file:</h3>
<strong>Your file most contain correct javscript formated script and 3 cases are not covered if your script contains lines like:
</br>
1. var exception1 = "// or /* or */";
</br>
2. var exception2 = '// or /* or */';
</br>
3. or strings containing : // or /* or */
</strong>
<pre id="file-content"></pre>

<h3>Parsed Output:</h3>
<div id='wrapper'></div>

<h4>RUN:</h4>
1. Create js file on your computer folowing corect format
<br>
2. Chose the File
<br>
3. Done

JavaScript

//read your file using FileReader
function readSingleFile(e) {
    var file = e.target.files[0];
      if (!file) {
        return;
      }
    var reader = new FileReader();
    reader.onload = function(e) {
    var contents = e.target.result;    
    displayFileLineByLine(contents);
  };
  reader.readAsText(file);
}

//attach event on file upload
document.getElementById('file-input')
  .addEventListener('change', readSingleFile, false);

//parse file input
function displayFileLineByLine(contents)
{
    var lines = contents.split('\n');
    var element = document.getElementById('file-content');
    var output = '';
    for(var line = 0; line < lines.length; line++){
        
        var normedline = stripOut(lines[line]);
        if (normedline.length > 0 )
        {
            output += normedline;
        }
    }
    element.innerHTML = output;  
}
// globa scope flag showing '/*' is open
var GlobalComentOpen = false;

//recursive line coments removal method
function stripOut(stringline, step){
        //index global coment start
        var igcS = stringline.indexOf('/*');
        //index global coment end
        var igcE = stringline.indexOf('*/');
        //index inline coment pos
        var iicP = stringline.indexOf('//');
        var gorecursive = false;
        if (igcS != -1)
        {
            gorecursive = true;
            if (igcS < igcE) { 
                stringline = stringline.replace(stringline.slice(igcS, igcE +2), "");
            }
            else if (igcS > igcE && GlobalComentOpen) {
                stringline = stringline.replace(stringline.slice(0, igcE +2), "");
                igcS = stringline.indexOf('/*');
                stringline = stringline.replace(stringline.slice(igcS, stringline.length), "");
            }
            else if (igcE == -1){
                GlobalComentOpen = true;
                stringline = stringline.replace(stringline.slice(igcS, stringline.length), "");
            }
            else
           ...