Nishil Faldu•10mo ago

Doc<'tablename'>

so i tried to do the Doc<'tablename'> directly in the query handler , 'Doc' only refers to a type, but is being used as a value here. why do you think is that?

20 Replies

ballingt•10mo ago

Sounds like a TypeScript syntax issue. Can you show the code? likely you need to name the parameter

Nishil FalduOP•10mo ago

import type { Doc } from "./_generated/dataModel";

export const updateListingById = mutation({
    args: {
        id: v.id("listings"),
        listing: Doc<"listings">,
    },
    handler: async ({ db }, { id, listing }) => {
        const existingListing = await db.get(id);

        if (!existingListing) {
            throw new ConvexError(
                "Listing not found. Please check the ID and try again.",
            );
        }

        await db.patch(id, listing);
    },
});

import type { Doc } from "./_generated/dataModel";

export const updateListingById = mutation({
    args: {
        id: v.id("listings"),
        listing: Doc<"listings">,
    },
    handler: async ({ db }, { id, listing }) => {
        const existingListing = await db.get(id);

        if (!existingListing) {
            throw new ConvexError(
                "Listing not found. Please check the ID and try again.",
            );
        }

        await db.patch(id, listing);
    },
});

ballingt•10mo ago

Ah sorry, I was thinking TypeScript syntax. You want the Convex validator syntax.

Nishil FalduOP•10mo ago

my bad if I wasn't clear

ballingt•10mo ago

no you're good, this is the more obvious thing to want The easiest way to do this now is to define the validator outside of the schema expression and give it a name and then import it

ballingt•10mo ago

Here's just the article for you, the first solution presented is what I mean by "define the validator outside the defineSchema expression" https://stack.convex.dev/argument-validation-without-repetition

Argument Validation without Repetition

A few more advanced techniques & helpers to further reduce duplication and accelerate your Convex workflow.

ballingt•10mo ago

oh actually this is the more advanced one, https://stack.convex.dev/types-cookbook looks like a better place to start

Types and Validators in TypeScript: A Convex Cookbook

It can be tough to wrangle types to behave how you want them to. Thankfully, Convex was designed to make the experience with types perfect. Learn why ...

Nishil FalduOP•10mo ago

Ah that does make me feel stupid lol. I was hoping for a one line type for validator from somewhere 😂. I appreciate your help now that I am here I might as well ask another question. So for patch, what if it fails - what's the best way of checking that and throwing error to the user? (would a simple try-catch be fine?)

ballingt•10mo ago

Ah sorry I missed this! @Nishil Faldu what kind of error do you want to throw? And I'm confused about why you want the try/catch if you want to throw an error

Nishil FalduOP•10mo ago

Like so far I have just been doing

try {
// patch here
} catch(error) {
  // report error and log error
}

try {
// patch here
} catch(error) {
  // report error and log error
}

was wondering if there was a better approach

ballingt•10mo ago

If that's all you're doing, you could skip that — because the patch will throw an error fi it fails and e.g. Sentry will receive the error without you throwing your own https://docs.convex.dev/production/integrations/exception-reporting But if you want to do your own validation first say, or you want to display a specific error to the user, they what you're doing looks reasonable. THen you're planning to catch the error on the client side? Ah Sentry integration is just for the pro plan, but regardless you'll see the error in your logs. But if you're trying to log the error to another service or put it in a DB table, then yeah catching it and doing that could make sense

Nishil FalduOP•10mo ago

that's pretty cool

ballingt•10mo ago

Roughly what you want is already what will happen

Nishil FalduOP•10mo ago

yeah I have been thinking of going pro for this project once I push it to prod

ballingt•10mo ago

but if you want to do something special, then yeah catching the error and then doing whatever you want is fine

Nishil FalduOP•10mo ago

sounds good. Thanks for your help

ballingt•10mo ago

If your goal is to use the error to deliver specific information to a browser, then note that you need to throw a special error, a ConvexError, to use the error to send data to the frontend normal errors throwin in a Convex function will be visible in dev but in prod all the details will be stripped away https://docs.convex.dev/functions/error-handling/application-errors Note that normally the db.patch() failing and throwing an error would cause the entire mutation to be aborted, rolling back any other changes in the mutation. But if you catch the error, that's not what happens — the other DB writes you made in the mutation function will still take effect so if that's not your goal, be sure to throw an error again after you do whatever it was you wanted to do in the catch(e) { ... }

Nishil FalduOP•10mo ago

oooohh i see. that's very helpful to know. i'd have totally missed that

 try {
            await db.patch(id, user);
        } catch (error) {
            console.log(error);
            throw new ConvexError(
                "We encountered an issue updating the user. Please try again later.",
            );
        }

 try {
            await db.patch(id, user);
        } catch (error) {
            console.log(error);
            throw new ConvexError(
                "We encountered an issue updating the user. Please try again later.",
            );
        }

so doing this will still rollback any other changes in the mutation? (because I threw an error in catch block?)

ballingt•10mo ago

Yep!

Nishil FalduOP•10mo ago

perfect. I think that was a good bunch of information. thanks again!

Doc<'tablename'>

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