When I want get refresh token in server side, seems like not correct

[GHChrisSu]

I use express and api-client want to get token from server side and access token looks like no problem

And when I use refresh token below in client side, error said refresh token is invalid

[GHChrisSu]

I use curl to do the test get same result, according to docs refresh token is same format to access token

[guilhermemalim]

I created a function to do this inside a custom-class MoneyButtonClient:

async refreshToken(refreshToken: string): Promise<JSON> {
    const baseURL = 'https://www.moneybutton.com/oauth/v1/token';

    const formBody = ParseURLEncodedBody({
      grant_type: 'refresh_token',
      refresh_token: refreshToken,
      client_id: mbConfig.oauth_id,
    });

    const raw_response = await fetch(baseURL, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/x-www-form-urlencoded',
      },
      body: formBody,
    });

    const response = await raw_response.json();

    return response;
  }

interface IParseURLEncodedBody {
  [key: string]: string;
}

export default function ParseURLEncodedBody(
  details: IParseURLEncodedBody,
): string {
  const formBody = [];
  for (const property in details) {
    const encodedKey = encodeURIComponent(property);
    const encodedValue = encodeURIComponent(details[property]);
    formBody.push(`${encodedKey}=${encodedValue}`);
  }
  const parsed_formBody = formBody.join('&');

  return parsed_formBody;
}