save file

Author: javascript-2020

code-dev/26-04-18/blob-base64-dataurl/blob-base64-dataurl.html

@@ -0,0 +1,92 @@
+
+
+<body></body>
+
+<script>
+
+
+(async()=>{
+
+      async function blob_b64(blob){
+      
+            var buf     = await blob.arrayBuffer();
+            var bytes   = new Uint8Array(buf);
+            var bin     = [...bytes].reduce((acc,byte)=>acc+=String.fromCharCode(byte),'');
+            var b64     = btoa(bin);
+            return b64;
+            
+      }//blob_b64
+      
+      function b64_blob(b64,type='text/plain'){
+      
+            var bin     = atob(b64);
+            var bytes   = [...bin].map(c=>c.charCodeAt(0));
+            var buf     = new Uint8Array(bytes);
+            var blob    = new Blob([buf],{type});
+            return blob;
+            
+      }//b64_blob
+      
+      function b64_dataurl(b64,type){
+      
+            var dataurl   = `data:${type};base64,${b64}`;
+            return dataurl;
+            
+      }//b64_datauri
+      
+      function dataurl_b64(dataurl){
+      
+            var i     = dataurl.indexOf(',')+1;
+            var b64   = dataurl.slice(i);
+            return b64;
+            
+      }//datauri_b64
+      
+      
+  //test
+  
+      var dataurl   =
+      'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA8AAAAPCAYAAAA71pVKAAAAAXNSR0IArs4c6QAAAiZJREFUOE9jZK'+
+      'AAMML0Xuro0P34+jWbbW/vOQYGhv+4zOwUYeDV0bMz3Ljv0Bmw5mdrV9aI8XE3MTy+x/j6zMn9B/cdz4i4ce8WsgFr5eUlVczNa7'+
+      '7wcFuefvKos2DX3rVgzfsqS63VhXgni319Y/jv9mWGT9evfzx5/320z/ufWxsYGJgcxMTS+ZUUmq/8+zcv/9SZlncMDJ9A+uDOZm'+
+      'BgYN1lrhmh8etTK8v7j7KfP//8dfnrvxyJf4wBjJycNruZmVIb3n1cw8DA8A/mImTNYLEEBgaBGD7mVpHfDBn/fv9j+viP4e0apv'+
+      '9BU/8wHEYPCwzNIAO2MDOEivxnXMT0/z/HP2bGb0cYWexKfv8+ix6IGJp3MjFkCvxnmPKdkfHjQUamQi9upmZmdqYvDa9/mm9iYP'+
+      'iMbACK5q0MDCmijAyzGJgZ/23+/z+m+S/DinY+dpUoCZZ9D37+W2n/8HsZstPhmtcyMFjIMjEeYmdlZL3IyDgr7sffLAYGhr8gm+'+
+      'aIsho68bHvXvvyl0Ppl19XMALsmCDvCf7f383fMjPeTfv42/wGA8NbZCfuFOVI4mFm9rB+8TUcZjvY5lZubvFoV5sXrLcvMZx7/6'+
+      '7X99nPEiwpjOmYMOeGSW+/Z6xgYHgGj+ckBgbe9pbKl3xPb3Ku33M4L+r268nYkucCdnblt//+8RX//n0eJZFsTY0JY/322Tpj6c'+
+      'a6ewwMH4nJL1jjmRiNIDUADZXPhFJZPA0AAAAASUVORK5CYII='
+      ;
+      
+      
+      var img             = document.createElement('img');
+      img.style.cssText   = 'border:1px solid lightgray;border-radius:5px;margin-right:20px;cursor:pointer;';
+      var nimg;
+      
+      nimg                = img.cloneNode();
+      nimg.src            = dataurl;
+      document.body.append(nimg);
+      
+      
+      var b64             = dataurl_b64(dataurl);
+      var blob            = b64_blob(b64,'image/png');
+      var type            = blob.type;    //  image/png
+      
+      nimg                = img.cloneNode(true);
+      nimg.src            = window.URL.createObjectURL(blob);
+      document.body.append(nimg);
+      
+      
+      var b64             = await blob_b64(blob);
+      var dataurl         = b64_dataurl(b64,'image/png');
+      
+      nimg                = img.cloneNode();
+      nimg.src            = dataurl;
+      document.body.append(nimg);
+      
+})();
+
+
+</script>
+
+
+