Yes. Using the authorization code flow client side will have almost the same effect as using the implicit grant flow.
There will be a few extra requests but the end result will be the same with some caveats:
- The implicit flow spec says the token must be in the URL's fragment so it doesn't leave the user-agent. You won't have this with the code flow
- You should not enable
refresh_tokens for the client.
Also the same security concerns as for the implicit flow apply. See RFC6748 section 10.16:
Authenticating resource owners to clients is out of scope for this
specification. Any specification that uses the authorization process
as a form of delegated end-user authentication to the client (e.g.,
third-party sign-in service) MUST NOT use the implicit flow without
additional security mechanisms that would enable the client to
determine if the access token was issued for its use (e.g., audience-
restricting the access token).
And on the client credentials front you were already covered:
Native applications that use the authorization code grant type SHOULD
do so without using client credentials, due to the native
application's inability to keep client credentials confidential.
Footnote: Be sure to read RFC6819 section 4.4.2 to avoid other common implicit flow pitfalls.