How to upload file (image) to NodeJS (and from NodeJS) - node.js

Question

I have the following code:
const formData = new FormData();
formData.append("filedata", myImage);
fetch("/extension/api/uploadtofb", {
method: "POST",
body: formData
})
If myImage is a base64 string representation (dataURL) of an image, multer considers it not as a file but as a text. Therefore it is found in req.body, not in req.file. How can I upload this image to my NodeJS (Express) server so it can be recognized and read as an image? (Doesn't need to use multer, I just followed instructions I found so far.)
I was able to work around it by converting the base64 string to blob and send it as blob instead. The image now can be correctly found in the req.file. But I need to send a post request with this image from the NodeJS (Express) server. FormData doesn't accept req.file or req.file.bufferin append. How can I convert received blob to a format, that can be accepted by FormData and sent with POST request?
I think that if the first problem can be solved, the second problem will also solve itself.

Answer 1

You can directly upload base64 image data
var base64Data = JSON.parse(res.body).data;
var filename = "test.png";
var base64_attachement = base64Data.replace(/-/g, '+').replace(/_/g, '/').replace(/ /g, '+');
filepath = (__dirname + './../../public/temp');
if (!fs.existsSync(filepath)) {
fs.mkdirSync(filepath, 0744); //Set Folder Permission
}
filepath = filepath + '/' + _filename;
//TempFilePath
require("fs").writeFile(filepath, base64_attachement, 'base64', function (err) {
console.log(err);
return cb(filepath);
});