Why select() always expects to have matches?

hi. i encountered this issue:

const [record] = await db
    .select()
    .from(day)
    .where(eq(id, 123456));

const [record] = await db
    .select()
    .from(day)
    .where(eq(id, 123456));

record is inferred to have a non-nullable type, even though the queried record with the ID 123456 may not exist in the database. Can anyone tell me if I am doing something wrong? I was migrating some queries to select() but this behavior makes it pretty unusable 😕 Thanks

4 Replies

Sillvva•7mo ago

Make sure you have noUncheckedIndexedAccess: true in your tsconfig.json file

{
    "compilerOptions": {
        "allowJs": true,
        "checkJs": true,
        "esModuleInterop": true,
        "forceConsistentCasingInFileNames": true,
+       "noUncheckedIndexedAccess": true,
        "noErrorTruncation": true,
        "resolveJsonModule": true,
        "skipLibCheck": true,
        "sourceMap": true,
        "strict": true
    }
}

{
    "compilerOptions": {
        "allowJs": true,
        "checkJs": true,
        "esModuleInterop": true,
        "forceConsistentCasingInFileNames": true,
+       "noUncheckedIndexedAccess": true,
        "noErrorTruncation": true,
        "resolveJsonModule": true,
        "skipLibCheck": true,
        "sourceMap": true,
        "strict": true
    }
}

Sillvva•7mo ago

https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-1.html#checked-indexed-accesses---nouncheckedindexedaccess

Documentation - TypeScript 4.1

TypeScript 4.1 Release Notes

Sillvva•7mo ago

In TypeScript without that option, when you have an array like string[] for example, string[0] is string. However, the array could be empty. That's where the option comes in and makes it string | undefined unless you check that the index exists.

const arr: string[] = [];
const [item] = arr; 
// Before option: item is string
// After option: item is string | undefined

if (item) {
  item // string
}

const arr: string[] = [];
const [item] = arr; 
// Before option: item is string
// After option: item is string | undefined

if (item) {
  item // string
}

The same is true for objects with unknown keys like const obj: Record<string, string> = {}

camiaei•7mo ago

thanks, however now I'm getting a couple of rather curious errors. I don't like typescript very much 😪

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Why select() always expects to have matches?