midnight holly
I'm trying to catch all the errors given in a useQuery (in particular useQueryWithStatus from convex-helpers) call but when:
const {
data: question,
isPending,
isError,
} = useQueryWithStatus(api.example.byId, {
id,
})
if he id does not match
args: {
id: zid("table"),
},
instead of having isError true, an error is raised in the frontend. is this supposed to happen?
cunning carbonBOT
Hi @midnight holly. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave:
Yes, this is expected behavior with Convex and the convex-helpers' useQueryWithStatus.
When you use a validator like zid("table") in your function arguments, Convex performs both type and runtime validation. If the id you pass does not match the expected format (i.e., it's not a valid branded ID for that table), Convex will throw a validation error before your query function even runs. This error is not caught by useQueryWithStatus as a regular query error—instead, it is thrown immediately and will bubble up to your React component, potentially triggering an error boundary or causing the component to crash if not handled.
This is confirmed in community discussions and support threads, where it's explained that the validator checks are enforced before your function logic, and if the argument doesn't pass validation, an error is thrown rather than returned as part of the query status. The recommended workaround is to use v.string() as your validator and then manually check and handle invalid IDs inside your function, allowing you to throw a ConvexError or return a custom error object that can be caught by useQueryWithStatus or similar hooks. This way, you can control the error handling flow and surface errors as part of your query status rather than as uncaught exceptions in the frontend [Value does not match validator].
In summary:
midnight holly
----------------------
Yes, this is expected behavior with Convex and the convex...
@cunning carbon
what is the best way to check at runtime that the id matches the Id<"table">, so i can handle everything properly without even invoking the query
cunning carbonBOT
Let me check the knowledge base for you again. One moment! :books:
The best way to check at runtime that an id matches the expected Id<"table"> (i.e., is a valid Convex document ID for a specific table) is to use the Convex argument validator v.id("table") (or zid("table") if using Zod) in your function arguments. This ensures that only valid IDs for the specified table are accepted by your backend function. However, as you noted, this will throw a validation error if the ID is invalid, and this error is not catchable as a normal query error in the frontend—it will throw immediately [Discord: Help understanding 'Validator error: Expected ID for table...'].
If you want to check the validity of the ID at runtime on the client side, before invoking the query, you have a couple of options:
Use v.string() and validate in the function:
Pass the ID as a string and, inside your function, use ctx.db.normalizeId to check if the string is a valid ID for the table. This allows you to handle invalid IDs gracefully and return a custom error or null, rather than throwing a validation error [Discord: Value does not match validator].
// In your Convex function
export const getById = query({
args: { id: v.string() },
handler: async (ctx, args) => {
const id = ctx.db.normalizeId("table", args.id);
if (!id) {
throw new ConvexError("Invalid ID");
}
const doc = await ctx.db.get(id);
// ... handle doc
},
});
Summary:
The recommended and most robust way is to use v.string() as the argument validator and then use ctx.db.normalizeId("table", id) inside your function to check validity at runtime. This allows you to handle errors gracefully and avoids uncatchable validation errors in your frontend [Discord: Value does not match validator].