# issueAccessToken method Null safety

Future<OAuthToken> issueAccessToken(

1. {required String authCode,
2. String? redirectUri,
3. String? appKey,
4. String? codeVerifier}

)

사용자 인증코드(`authCode`)를 이용하여 신규 토큰 발급을 요청합니다. `codeVerifier`는 사용자 인증 코드 verifier로 사용합니다.

## Implementation

    Future<OAuthToken> issueAccessToken({
      required String authCode,
      String? redirectUri,
      String? appKey,
      String? codeVerifier,
    }) async {
      final data = {
        Constants.code: authCode,
        Constants.grantType: Constants.authorizationCode,
        Constants.clientId: appKey ?? KakaoSdk.platformAppKey,
        Constants.redirectUri: redirectUri ?? await _platformRedirectUri(),
        Constants.codeVerifier: codeVerifier,
        ...await _platformData()
      };
      return await _issueAccessToken(data);
    }