Stripe error: "You may only specify one of these parameters: default_price_data, type."

Attempting to create a product on stripe dashboard through node-fetch.

code snippet:

 async createProduct(data) {
      try {
            const response = await fetch(url, {
                method: 'POST',
                headers: {
                    'Authorization': `Bearer ${process.env.STRIPE_SECRET_KEY}`,
                    'Content-Type': 'application/x-www-form-urlencoded'
                },

            body: new URLSearchParams(Object.entries(data)).toString()}).then(res => res.json());
            return { data: response };
            } catch (err) {
            return { error: err.message };
            }
        }

JSON Body:

{
  "name": "product",
  "active": true,
  "default_price_data": {
    "currency": "eur",
    "unit_amount": "1"
  },
  "description": "myprod",
  "type": "service"
}

without the default price data it creates the product normally, but it's without a price of course. i need help with the JSON body to initialize properly the default_price_data stuff and in the future for similar data structures.

Specifying type=service on a product is not something you should do if your API version is less than 6 years old, which I hope it is.
https://docs.stripe.com/upgrades#2018-02-05

You should remove the type argument from your payload, it should always be service by default anyhow.