DateTime values wrongly typed in Prisma Client

Bug description

When using start as an ISO string in a date library, I get this error. There are no runtime errors as it’s actually a string:

// Argument of type [see below] is not assignable to parameter of type 'string'
DateTime.fromISO(start)

Prisma schema

start          DateTime

Lets console.log(start)

1970-01-01T00:00:00.000Z

TypeScript type for start

start: {
    toString: () => string;
    toDateString: () => string;
    toTimeString: () => string;
    toLocaleString: {
        (): string;
        (locales?: string | string[] | undefined, options?: Intl.DateTimeFormatOptions | undefined): string;
    };
    ... 40 more ...;
    [Symbol.toPrimitive]: {
        ...;
    };
}

Prisma Version

prisma                  : 3.11.1
@prisma/client          : 3.11.1
Current platform        : debian-openssl-1.1.x
Query Engine (Node-API) : libquery-engine 1a2506facaf1a4727b7c26850735e88ec779dee9 (at node_modules/@prisma/engines/libquery_engine-debian-openssl-1.1.x.so.node)
Migration Engine        : migration-engine-cli 1a2506facaf1a4727b7c26850735e88ec779dee9 (at node_modules/@prisma/engines/migration-engine-debian-openssl-1.1.x)
Introspection Engine    : introspection-core 1a2506facaf1a4727b7c26850735e88ec779dee9 (at node_modules/@prisma/engines/introspection-engine-debian-openssl-1.1.x)
Format Binary           : prisma-fmt 1a2506facaf1a4727b7c26850735e88ec779dee9 (at node_modules/@prisma/engines/prisma-fmt-debian-openssl-1.1.x)
Default Engines Hash    : 1a2506facaf1a4727b7c26850735e88ec779dee9
Studio                  : 0.458.0
Preview Features        : fullTextSearch

[marc-on-github]

I just have the same problem

[aqrln]

@ekerik220 in your case Prisma returns a Date. It is then lost and converted to a string due to serialization to JSON by Remix. You can see what’s happening by adding some logs on the server side as well.

Logs:

createdAt type in getNote: object
createdAt instanceof Date: true
createdAt data type in component: string

Diff:

diff --git a/app/models/note.server.ts b/app/models/note.server.ts
index ba56b53..4f23cc0 100644
--- a/app/models/note.server.ts
+++ b/app/models/note.server.ts
@@ -4,15 +4,18 @@ import { prisma } from "~/db.server";
 
 export type { Note } from "@prisma/client";
 
-export function getNote({
+export async function getNote({
   id,
   userId,
 }: Pick<Note, "id"> & {
   userId: User["id"];
 }) {
-  return prisma.note.findFirst({
+  const note = await prisma.note.findFirst({
     where: { id, userId },
   });
+  console.log("createdAt type in getNote:", typeof note?.createdAt);
+  console.log("createdAt instanceof Date:", note?.createdAt instanceof Date);
+  return note;
 }
 
 export function getNoteListItems({ userId }: { userId: User["id"] }) {
diff --git a/app/routes/notes/$noteId.tsx b/app/routes/notes/$noteId.tsx
index b326f37..da07201 100644
--- a/app/routes/notes/$noteId.tsx
+++ b/app/routes/notes/$noteId.tsx
@@ -36,7 +36,7 @@ export default function NoteDetailsPage() {
   const data = useLoaderData() as LoaderData;
 
   // Typescript says createdAt is a Date, but the console log says it's a string.
-  console.log("createdAt data type:", typeof data.note.createdAt);
+  console.log("createdAt data type in component:", typeof data.note.createdAt);
 
   return (
     <div>