perf: improve type Auth

[himself65]

Move it on top of Auth to reduce some deeper type inference.

Reduce perf from ~9.5s to ~8.7s

Summary by cubic

Made Auth generic and plugin-aware to provide precise typings for api, options, $Infer, and merged $ERROR_CODES. Added type tests to validate default Auth and plugin error code merging.

• Refactors
  • Introduced Auth and updated betterAuth to return Auth.
  • api now derives from router endpoints via FilterActions; removed InferAPI casting.
  • $ERROR_CODES types merge InferPluginErrorCodes with BASE_ERROR_CODES.
  • $Infer exposes session/user inferred from Options and includes plugin types.
  • Added vitest type tests for default Auth and custom plugin $ERROR_CODES.

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@better-auth/cli

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@better-auth/core

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@better-auth/expo

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@better-auth/sso

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@better-auth/stripe

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commit: 286f881

[cubic-dev-ai]

No issues found across 2 files

[artimath]

So, I still had the same issues with this version, but then codex figured it out... somehow. Not sure if it will crash during runtime, but it did resolve the types cleanly WHILE exactOptionalPropertyTypes is true

here is a PR/branch/commit with the fix: artimath/tanstack-effect-cloudflare-template#1

here is the code that changed it, adding $InferAuth to the createAuthClient options:

import { adminClient, emailOTPClient, inferAdditionalFields, magicLinkClient, multiSessionClient, organizationClient, passkeyClient, twoFactorClient, } from "better-auth/client/plugins"; import { InferAuth } from "better-auth/client"; import { createAuthClient } from "better-auth/react"; import { env } from "@/lib/env.client"; import { ac, admin as adminRole, superadmin as superAdminRole, user as userRole } from "./permissions"; import type { auth } from "@/lib/auth/auth"; export const authClient = createAuthClient({ baseURL: env.VITE_SERVER_URL, plugins: [ inferAdditionalFields<typeof auth>(), twoFactorClient(), passkeyClient(), adminClient({ ac, roles: { user: userRole, admin: adminRole, superadmin: superAdminRole, }, }), organizationClient(), emailOTPClient(), magicLinkClient(), multiSessionClient(), ], $InferAuth: InferAuth<typeof auth>(), <--- magic fix? }); export type AuthClient = typeof authClient; export type Session = AuthClient["$Infer"]["Session"]; export type SessionUser = Session["user"]; export type Organization = AuthClient["$Infer"]["Organization"]; export type ActiveOrganization = AuthClient["$Infer"]["ActiveOrganization"];

maybe it's a mirage, but on the off-chance it isn't, i want to share it since i saw a lot of people running into it

@himself65 thank you for creating this and tending to it