dataURItoBlob

dataURItoBlob.js

  dataURItoBlob = (dataURI) => {
    // convert base64 to raw binary data held in a string
    // doesn't handle URLEncoded DataURIs - see SO answer #6850276 for code that does this
    var byteString = atob(dataURI.split(',')[1]);

    // separate out the mime component
    var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0]

    // write the bytes of the string to an ArrayBuffer
    var ab = new ArrayBuffer(byteString.length);

    // create a view into the buffer
    var ia = new Uint8Array(ab);

    // set the bytes of the buffer to the correct values
    for (var i = 0; i < byteString.length; i++) {
        ia[i] = byteString.charCodeAt(i);
    }

    // write the ArrayBuffer to a blob, and you're done
    var blob = new Blob([ab], {type: mimeString});
    return blob;

  }