TokenCache typing problem

[bzums]

If initialising the TokenCache like:

const oAuthConfig = {
  credentialsDir,
  accessTokenEndpoint,
  tokenInfoEndpoint,
  grantType: OAuthGrantType.CLIENT_CREDENTIALS_GRANT
};

const cache = new TokenCache(tokenConfig, oAuthConfig);

we currently get the following error:

> src/services/token-cache.ts(29,38): error TS2345: Argument of type '{ credentialsDir: string; accessTokenEndpoint: string; tokenInfoEndpoint: string; grantType: OAuthGrantType; }' is not assignable to parameter of type 'TokenCacheOAuthConfig'.
>   Type '{ credentialsDir: string; accessTokenEndpoint: string; tokenInfoEndpoint: string; grantType: OAuthGrantType; }' is not assignable to type 'CredentialsClientConfig & GrantConfigBase & { grantType: OAuthGrantType.REFRESH_TOKEN_GRANT; refreshToken: string; } & { tokenInfoEndpoint: string; }'.
>     Type '{ credentialsDir: string; accessTokenEndpoint: string; tokenInfoEndpoint: string; grantType: OAuthGrantType; }' is not assignable to type 'CredentialsClientConfig'.
>       Property 'clientId' is missing in type '{ credentialsDir: string; accessTokenEndpoint: string; tokenInfoEndpoint: string; grantType: OAuthGrantType; }'.

which can be fixed via an explicitly typing:

const oAuthConfig: TokenCacheOAuthConfig = { ... };

However, that should not be necessary for the user. We have to investigate further why this problem occurs.

[ISO50]

@bzums

When using the above method Typescript infers OAuthGrantType instead of OAuthGrantType.CLIENT_CREDENTIALS_GRANT for the grantType field.

This can be fixed by:

1. oAuthConfig: TokenCacheOAuthConfig
2. inlining:

const cache = new TokenCache(tokenConfig, {
  credentialsDir: 'credentialsDir',
  accessTokenEndpoint: 'accessTokenEndpoint',
  tokenInfoEndpoint: 'tokenInfoEndpoint',
  grantType: OAuthGrantType.CLIENT_CREDENTIALS_GRANT
});

3. Or using Type assertions:

const oAuthConfig = {
  credentialsDir: 'credentialsDir',
  accessTokenEndpoint: 'accessTokenEndpoint',
  tokenInfoEndpoint: 'tokenInfoEndpoint',
  grantType: OAuthGrantType.CLIENT_CREDENTIALS_GRANT as OAuthGrantType.CLIENT_CREDENTIALS_GRANT,
};

---

Maybe using String Literals instead of Enums could make that work without this workarounds.

[ISO50]

One of the underlying problems, read here: microsoft/TypeScript#9489

[ISO50]

https://stackoverflow.com/questions/36415722/typescript-string-literal-with-duck-typed-object

[ISO50]

Fixed by #171