JSFiddle - React, Tailwind, and code Playground

by Akihiko Kusanagi

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/upng-js/2.1.0/UPNG.min.js"></script>

JavaScript

var buff = request('https://www.jma.go.jp/jp/radnowc/imgs/radar/000/201910142355-00.png', function(data) {
  var img = UPNG.decode(data);
  var rgba = UPNG.toRGBA8(img)[0];
  
  alert('width: ' + img.width + ', height: ' + img.height);
});

function request(url, callback) {
  var xhr = new XMLHttpRequest();

  xhr.open('GET', url);
  xhr.responseType = 'arraybuffer';
  xhr.onreadystatechange = function() {
    var data;

    if (xhr.readyState === 4) {
      if (xhr.status === 200) {
        callback.call(xhr.response);
      }
    }
  };
  xhr.send();
}