Add custom header in FormData request - node.js

Question

I have a Node function that uploads a file to an endpoint using FormData:
const uploadFile = (filepath) => {
return new Promise((resolve, reject) => {
const formData = new FormData();
// Add file
formData.append("file", fs.createReadStream(filepath));
formData.submit(`${API_URL}/v2/upload_file`, (error, res) => {
if (error) {
return reject(error);
}
if (res.statusCode !== 201) {
return reject(res.statusMessage);
}
return resolve(res);
});
});
};
This works fine. The problem is that after an update on the endpoint, a custom header with a token is now required:
'x-session-token': 'abc123'
I can't find a way to add this token. formData.append() only adds key-values to the body. I was reading the node source code but can't find a method or a way to add options like headers.
I also tried using fetch() adding the headers, but is not parsing the multipart/form-data body data in a valid format.
Any ideas?

Answer 1

From the documentation...
In case you need to also send custom HTTP headers with the POST request, you can use the headers key in first parameter of form.submit()
const url = new URL(`${API_URL}/v2/upload_file`);
formData.submit({
headers: { "x-session-token": "abc123" },
host: url.hostname,
path: url.pathname,
port: url.port,
protocol: url.protocol,
}, (error, res) => {
// ...
});
IMO this is pretty clunky, particularly having to parse the URL into its components. It also doesn't support query parameters.
I would prefer to use fetch()
const uploadFile = async (filepath) => {
const formData = new FormData();
// Add file
formData.append("file", fs.createReadStream(filepath));
const res = await fetch(`${API_URL}/v2/upload_file`, {
method: "POST",
body: formData,
headers: {
...formData.getHeaders(),
"x-session-token": "abc123",
},
});
if (!res.ok) {
throw new Error(res.statusText);
}
return res.json(); // or res.text()
};