message: More specfic typing
diff: @@ -43,7 +43,7 @@ class AuthorizeController extends Controller {
  const responseType = ctx.query.response_type;
  const redirectUri = ctx.query.redirect_uri;
  const codeChallenge = ctx.query.code_challenge;
  - const codeChallengeMethod = ctx.query.code_challenge_method ? ctx.query.code_challenge_method : 'plain';
  + const codeChallengeMethod = ctx.query.code_challenge_method ? (<'S256'>ctx.query.code_challenge_method) : 'plain';
  const grantType = responseType === 'code' ? 'authorization_code' : 'implicit';
  try {
  @@ -119,7 +119,7 @@ class AuthorizeController extends Controller {
  const redirectUri = ctx.request.body.redirect_uri;
  const responseType = ctx.request.body.response_type;
  const codeChallenge = ctx.request.body.code_challenge;
  - const codeChallengeMethod = ctx.request.body.code_challenge_method;
  + const codeChallengeMethod = ctx.request.body.code_challenge_method ? (<'S256'>ctx.request.body.code_challenge_method) : 'plain';
  const grantType = responseType === 'code' ? 'authorization_code' : 'implicit';
  try {
  @@ -218,7 +218,7 @@ class AuthorizeController extends Controller {
  redirectUri: string,
  state: string|undefined,
  codeChallenge: string|undefined,
  - codeChallengeMethod: string|undefined,
  + codeChallengeMethod: 'S256' | 'plain' | undefined
  ) {
  const code = await oauth2Service.generateCodeForUser(
  