Refund captured payment

//native

type Paypal = {

  clientId: string;

  clientSecret: string;

};

async function getToken(auth: Paypal): Promise<string> {

  const url = new URL(`https://api-m.paypal.com/v1/oauth2/token`);

  const response = await fetch(url, {

    method: "POST",

    headers: {

      Authorization: `Basic ${btoa(`${auth.clientId}:${auth.clientSecret}`)}`,

    },

    body: new URLSearchParams({

      grant_type: "client_credentials",

    }),

  });

  if (!response.ok) {

    const text = await response.text();

    throw new Error(`Could not get token: ${response.status} ${text}`);

  }

  const json = await response.json();

  return json.access_token;

}

/**

 * Refund captured payment

 * Refunds a captured payment, by ID. For a full refund, include an empty payload in the JSON request body. For a partial refund, include an amount object in the JSON request body.

 */

export async function main(

  auth: Paypal,

  capture_id: string,

  PayPal_Request_Id: string,

  Prefer: string,

  PayPal_Auth_Assertion: string,

  body: {

    amount?: { currency_code: string; value: string };

    custom_id?: string;

    invoice_id?: string;

    note_to_payer?: string;

    payment_instruction?: {

      platform_fees?: {

        amount: { currency_code: string; value: string };

        payee?: { email_address?: string; merchant_id?: string };

      }[];

    };

  },

) {

  const token = await getToken(auth);

  const url = new URL(

    `https://api-m.paypal.com/v2/payments/captures/${capture_id}/refund`,

  );

  const response = await fetch(url, {

    method: "POST",

    headers: {

      "PayPal-Request-Id": PayPal_Request_Id,

      Prefer: Prefer,

      "PayPal-Auth-Assertion": PayPal_Auth_Assertion,

      "Content-Type": "application/json",

      Authorization: "Bearer " + token,

    },

    body: JSON.stringify(body),

  });

  if (!response.ok) {

    const text = await response.text();

    throw new Error(`${response.status} ${text}`);

  }

  return await response.json();

}