I need to read a locally stored image, embed the image to a form with form-data using the GraphQL multipart request specification, then perform a POST request to a graphql server with the body of the request being the form data itself.

I read the image using fs.readFile, and use the data as an argument to my post data function:

fs.readFile('./location/to/image/image.jpg', (err, data) => {
    if (err) {
        throw (err);
    }

    postData(data);
});

My postData function goes as follows:

function postData(readable) {
    /** Create form data */
    const requestBody = new FormData();

    /** Define the query */
    const sdl = `
        mutation ($image: Upload!) {
            testUpload(image: $image){
            code
            success
            message
            }
        }
    `;

    /** Follow instructions according to graphql multipart request specification 
     * https://github.com/jaydenseric/graphql-multipart-request-spec */
    requestBody.append(
        'operations',
        JSON.stringify({
            query: sdl,
            variables: { image: null },
        })
    );

    requestBody.append(
        'map',
        JSON.stringify({
            0: ['variables.image'],
        })
    );

    requestBody.append('0', readable);

    /** Submit the form */
    return new Promise((resolve, reject) => {
        requestBody.submit('http://localhost:4000/api/graphql', (err, res) => {
            if (err) {
                console.error(err);
                reject(err);
            } else {
                let body = '';
                res.on('readable', () => {
                    body += res.read();
                });

                res.on('end', () => {
                    resolve(JSON.parse(body));
                });
            }
        });
    });
}

What happens is, I successfully hit my API and my resolver, but the file's mimetype is received as application/octet-stream.

I am assumming that I am not reading the data correctly, or something else entirely.

I would truely appreciate any help. Thank you.