JSFiddle - React, Tailwind, and code Playground

HTML

<input type='file' accept='image/*' onchange='openFile(event)'><br>
<img id='output'>

JavaScript

var openFile = function(event) {
    var input = event.target;
    var reader = new FileReader();
    reader.onload = fileLoaded;
    reader.readAsDataURL(input.files[0]);
 };

var fileLoaded = function (event) {
    var dataURL = event.target.result;
    var output = document.getElementById('output');
    output.src = dataURL;

    // Do your other stuff here with dataURL
    console.log(dataURL);
};