JS Convert base64 string to blob - JackHu88/Comm GitHub Wiki

https://ourcodeworld.com/articles/read/322/how-to-convert-a-base64-image-into-a-image-file-and-upload-it-with-an-asynchronous-form-using-jquery

var options = {
                    height: 30,//高度
                    displayValue: false,//是否在条形码下方显示文字
                    fontSize: 10,//设置文本的大小
                    background: "#fff",//设置条形码的背景
                    lineColor: "#000",//设置条和文本的颜色。
                    margin: 0,//设置条
                    fontOptions: "Bold"
                }
$("#barcode").JsBarcode("2018-15-002", options);

var ImageURL=$("#barcode").attr("src");
var block = ImageURL.split(";");
// Get the content type of the image
var contentType = block[0].split(":")[1];// In this case "image/gif"
// get the real base64 content of the file
var realData = block[1].split(",")[1];// In this case "R0lGODlhPQBEAPeoAJosM...."

// Convert it to a blob to upload
var blob = b64toBlob(realData, contentType);

function b64toBlob(b64Data, contentType, sliceSize) {
        contentType = contentType || '';
        sliceSize = sliceSize || 512;

        var byteCharacters = atob(b64Data);
        var byteArrays = [];

        for (var offset = 0; offset < byteCharacters.length; offset += sliceSize) {
            var slice = byteCharacters.slice(offset, offset + sliceSize);

            var byteNumbers = new Array(slice.length);
            for (var i = 0; i < slice.length; i++) {
                byteNumbers[i] = slice.charCodeAt(i);
            }

            var byteArray = new Uint8Array(byteNumbers);

            byteArrays.push(byteArray);
        }

      var blob = new Blob(byteArrays, {type: contentType});
      return blob;
}

$pnp.sp.web.getFolderByServerRelativeUrl(_spPageContextInfo.webServerRelativeUrl + "/Library/" + "/2018-15-003").files
.add("barcode.png",blob, true)
.catch(function (error) {
         console.log(error)
})