JSFiddle - React, Tailwind, and code Playground

HTML

<input id="files"  type="file" name="files[]" multiple />
<output id="list"></output>

JavaScript

function handleFileSelect(evt) {
 	var files = evt.target.files;
  
    var reader = new FileReader();
    var content;
	reader.onload = function (evt) {
    content = evt.target.result;
}
    reader.readAsText(files);
  }

  document.getElementById('files').addEventListener('change', handleFileSelect, false);