JSFiddle - React, Tailwind, and code Playground

HTML

<input type='file'/>
<img id='preview'/>

JavaScript

var $preview = document.getElementById('preview');

document.querySelector('input').addEventListener('change', function(){
    var reader = new FileReader(),
        file = this.files[0];
    
    if(file)
        reader.readAsDataURL(file);
    else
        $preview.src = '';
    
    reader.onloadend = function(){
        $preview.src = reader.result;
    };
});