JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://unpkg.com/prop-types@15.5.10/prop-types.js"></script>
<script src="https://unpkg.com/react@16/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
<!DOCTYPE html>
<html>
<head>
	<title> test greet app </title>
	<style>
		* {
			font-size: 30px;
		}
	</style>
</head>
<body>
	<input id="image-selector" type="file">
	<button id="predict-button">Predict</button>
	<p style="font-weight:bold">Predictions</p>
	<p>angry: <span id="angry"></span></p>
	<p>scared:   <span id="scared"></span></p>
	<p>happy:   <span id="happy"></span></p>
	<p>sad:    <span id="sad"></span></p>
	<p>surprised:   <span id="surprised"></span></p>
	<p>neutral:    <span id="neutral"></span></p>
	<img id="selected-image" src=""/>

	<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>

</body>
</html>

Babel + JSX

let base64Image;
$("#image-selector").change(function() {
  let reader = new FileReader();
  reader.onload = function(e) {
    let dataURL = reader.result;
    $('#selected-image').attr("src",dataURL);
    base64Image = dataURL.replace("data:image/jpeg;base64,","");
    console.log(base64Image);
  }
  reader.readAsDataURL($("#image-selector")[0].files[0]);
  $("#angry").text("");
  $("#scared").text("");
  $("#happy").text("");
  $("#sad").text("");
  $("#surprised").text("");
  $("#neutral").text("");

});

$("#predict-button").click(function(event){
  let message = {
    image: base64Image
  }
  console.log(message);
  $.post("http://127.0.0.1:5000/predict",JSON.stringify(message),function(response){
    $("#angry").text(response.prediction.angry.toFixed(6));
    $("#scared").text(response.prediction.scared.toFixed(6));
    $("#happy").text(response.prediction.happy.toFixed(6));
    $("#sad").text(response.prediction.sad.toFixed(6));
    $("#surprised").text(response.prediction.surprised.toFixed(6));
    $("#neutral").text(response.prediction.neutral.toFixed(6));
    console.log(response);
  });
});