import { db } from "@/backend/database/drizzle/db";
import { userAddresses } from "@/backend/database/schema/schema";
import { eq } from "drizzle-orm";

export const fetchUserAddresses = async (userId: string) => {
  
    const isServer = typeof window === "undefined";

    if (isServer) {
      console.log("Running on the server");
    } else {
      console.log("Running on the client");
    }
  
  
    try {
    const existingUserAddresses = await db.query.userAddresses.findMany({
      where: eq(userAddresses.userId, userId),
    });
    return existingUserAddresses;
  } catch (error) {
    console.log("Error fetching userAddresses", error);
    throw new Error("Error fetching userAddresses");
  }
};

So, judging by the console.log, this function runs on the server. Evidently, that makes sense. What I don't understand is that I haven't explicitly labeled it with the "use server" directive.

How does Next.js decide whether this standalone function should run on the server or on the client? Notice this function is not declared under the src/app folder, nor is it part of an API route.

Thanks in advance! for your help