BA
Better Auth•2mo ago
basic white guy

Incorrect type inference with additionalFields inside a monorepo

I am using BetterAuth inside the packages directory of my Turborepo.
export type Session = typeof auth.$Infer.Session;
export type User = (typeof auth.$Infer.Session)["user"];
export type Session = typeof auth.$Infer.Session;
export type User = (typeof auth.$Infer.Session)["user"];
According to the BetterAuth documentation, the Session type should be inferred correctly using typeof auth.$Infer.Session. However, when I hover over User, I get the following inferred type:
type User = {
    id: string;
    email: string;
    emailVerified: boolean;
    name: string;
    createdAt: Date;
    updatedAt: Date;
    image?: string | null | undefined | undefined;
}
type User = {
    id: string;
    email: string;
    emailVerified: boolean;
    name: string;
    createdAt: Date;
    updatedAt: Date;
    image?: string | null | undefined | undefined;
}
This does not include the additional fields I defined in user.additionalFields. Am I missing a step to ensure the custom fields are included in the inferred type?
TypeScript | Better Auth
Better Auth TypeScript integration.

tester.ts

2 Replies
VitaBjorn
VitaBjorn•3w ago
+1 I added a role additional field to the user it's not reflecting on types. Would be great to know how to fix it or if we're missing something.
VitaBjorn
VitaBjorn•3w ago
Ok, so this is what I was missing. Adding the inferAdditionalFields plugin to the client! https://www.better-auth.com/docs/concepts/typescript#inferring-additional-fields-on-client
TypeScript | Better Auth
Better Auth TypeScript integration.

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