File upload error ( REST /v1/files)

API
1

file content:
{“prompt”: “customer info”, “completion”: “select * from g_customer”}

nodejs:

const FILE_PATH = __dirname+‘/data.txt’;

const file_data = fs.readFileSync(FILE_PATH);
const fileblob = Buffer.from(file_data,‘utf8’);

const formData = new FormData();

formData.append(‘purpose’, ‘fine-tune’);
formData.append(‘file’,fileblob, {
filename: ‘myTrainingFile.jsonl’,
contentType: ‘text/plain; charset=utf8’
});

fetch(‘https://api.openai.com/v1/files’, {
method: ‘POST’,
headers: {
//‘Content-Type’: ‘text/plain; charset=utf8’,
//‘Content-Type’: ‘multipart/form-data’,

    'Authorization': `Bearer ${apiKey}`,
	//...formData.getHeaders()
},
body:formData

}).then(res=>{console.log(JSON.parse(res))})

openai response: “Invalid Content-Type header (), expected multipart/form-data. (HIN
T: If you’re using curl, you can pass -H ‘Content-Type: multipart/form-data’)”

But after I add the ‘Content-Type: multipart/form-data’, got error msg below:
“‘file’ is a required property”

Someone could help me plz?