A better auth plugin that allows you to quickly create and login as different users

debugLoginPlugin.ts

import { BetterAuthPlugin, User } from "better-auth";
import { createAuthEndpoint } from "better-auth/api";
import { setSessionCookie } from "better-auth/cookies";
import z from "zod";

// A debug plugin that allows you to quickly create and login as different users.
// Usage: Visit "/debug-login?name=myuser" in your browser to get a session for myuser@example.com
// Note: only add to your plugin list if not on production
export const debugLoginPlugin = () => {
  return {
    id: "debug-login-plugin",
    endpoints: {
      postDebugLogin: createAuthEndpoint(
        "/debug-login",
        {
          method: "GET",
          query: z.object({
            name: z.string().regex(/^[a-zA-Z0-9-]+$/),
          }),
        },
        async (ctx) => {
          // Hardcoding @example.com is a safeguard in case this is added to production in error
          const email = `${ctx.query.name}@example.com`;
          let user: User | null = await ctx.context.adapter.findOne({
            model: "user",
            where: [{ field: "email", value: email }],
          });
          if (!user) {
            user = await ctx.context.adapter.create({
              model: "user",
              data: {
                email: email,
                name: ctx.query.name,
                emailVerified: true,
              },
            });
          }
          if (!user) {
            throw new Error("Oopsie doodle");
          }
          const session = await ctx.context.internalAdapter.createSession(user.id);
          ctx.context.setNewSession({
            session,
            user,
          });
          await setSessionCookie(ctx, {
            session,
            user,
          });
          throw ctx.redirect("/");
        },
      ),
    },
  } satisfies BetterAuthPlugin;
};