Kysely•4mo ago

Error: don't await SelectQueryBuilder instances directly.

To execute the query you need to call execute or executeTakeFirst. I'm trying to create a function that enhances the query (SelectQueryBuilder) with pagination, sorting and filtering options that are derived from a HTTP request. This function looks like:

  async applyQueryParams<DB, TB extends keyof DB, O>(qb: SelectQueryBuilder<DB, TB, O>): Promise<SelectQueryBuilder<DB, TB, O>> {
    const data = await this.getValidatedData<PaginationSchema & SortSchema & FilterSchema>();
    const page = .. // derive page
    const pageSize = .. // derive page size
    const sort = .. // derive sort
    const filter = .. // derive filter

    console.log("Query builder before pagination:", qb);

    qb = qb.limit(pageSize);
    qb = qb.offset((page - 1) * pageSize);

    console.log("Query builder after pagination:", qb);

    return qb;
  }

  async applyQueryParams<DB, TB extends keyof DB, O>(qb: SelectQueryBuilder<DB, TB, O>): Promise<SelectQueryBuilder<DB, TB, O>> {
    const data = await this.getValidatedData<PaginationSchema & SortSchema & FilterSchema>();
    const page = .. // derive page
    const pageSize = .. // derive page size
    const sort = .. // derive sort
    const filter = .. // derive filter

    console.log("Query builder before pagination:", qb);

    qb = qb.limit(pageSize);
    qb = qb.offset((page - 1) * pageSize);

    console.log("Query builder after pagination:", qb);

    return qb;
  }

this function needs to async as the getValidatedData() is also async in a handler I call applyQueryParams like:

async handle(c: C) {

    let qb = c.var.mydb
      .selectFrom('customer')
      .selectAll('customer');

    console.log("Before applying query params:", qb);

    qb = await this.applyQueryParams(qb);

    console.log("After applying query params:", qb);

    const customers = await qb.execute();

async handle(c: C) {

    let qb = c.var.mydb
      .selectFrom('customer')
      .selectAll('customer');

    console.log("Before applying query params:", qb);

    qb = await this.applyQueryParams(qb);

    console.log("After applying query params:", qb);

    const customers = await qb.execute();

but this fails with:

Before applying query params: SelectQueryBuilderImpl {}
Query builder before pagination: SelectQueryBuilderImpl {}
Query builder after pagination: SelectQueryBuilderImpl {}
✘ [ERROR] Error: don't await SelectQueryBuilder instances directly. To execute the query you need to call `execute` or `executeTakeFirst`.

Before applying query params: SelectQueryBuilderImpl {}
Query builder before pagination: SelectQueryBuilderImpl {}
Query builder after pagination: SelectQueryBuilderImpl {}
✘ [ERROR] Error: don't await SelectQueryBuilder instances directly. To execute the query you need to call `execute` or `executeTakeFirst`.

and I don't understand what is wrong 😦 .... this seems not to be correct: qb = await this.applyQueryParams(qb);, but I need to await it. anybody an idea what I'm doing wrong?

Solution:

If you return a thenable object from an async function its then method gets called. Kysely query builders all have a then method that throws that exception. It's there because many other query builders and ORMs allow you to do stuff like

const result = await db.selectFrom('person').selectAll()

const result = await db.selectFrom('person').selectAll()

...

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6 Replies

Marcel OverdijkOP•4mo ago

I found this related issue as well: https://github.com/kysely-org/kysely/issues/838 but it does not give a solution, or maybe there is none, and an async function can't return a query builder?

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Issue I have a database repository class that internally uses Kysely for querying. There are two methods that share a similar query, so I have a helper function to create the query. To fill where p...

Marcel OverdijkOP•4mo ago

https://github.com/kysely-org/kysely/issues/693#issuecomment-2332606627

GitHub

Using sql helper in promise chains causes unexpected preventAwait e...

Here's a simple example: import { sql } from 'kysely' // a plain promise for the example, but this could be a value determined inside a transaction // or as part of some other promise c...

Marcel OverdijkOP•4mo ago

https://github.com/kysely-org/kysely/pull/748#issuecomment-2332608963

GitHub

A way to disable 'preventAwait' by wirekang · Pull Request #748 · k...

Although @koskimas closed #693 as 'wontfix', I'm suggesting a way to disable the behavior of preventAwait, with a small footprint. We often returning non-Promise value in as...

Solution

koskimas•4mo ago

const result = await db.selectFrom('person').selectAll()

const result = await db.selectFrom('person').selectAll()

and Kysely doesn't. If we didn't have the then method, we'd get a lot of issues about queries not getting executed. Just wrap the return value to something not thenable. For example { qb }

Marcel OverdijkOP•4mo ago

thx @koskimas I already was using that (hopefully temporary) when I got the error:

  async applyQueryParams<DB, TB extends keyof DB, O>(qb: SelectQueryBuilder<DB, TB, O>): Promise<{ qb: SelectQueryBuilder<DB, TB, O> }> {
    ..
    return { qb };
  }

  async applyQueryParams<DB, TB extends keyof DB, O>(qb: SelectQueryBuilder<DB, TB, O>): Promise<{ qb: SelectQueryBuilder<DB, TB, O> }> {
    ..
    return { qb };
  }

and then using it like:

qb = (await this.applyQueryParams(qb)).qb;

qb = (await this.applyQueryParams(qb)).qb;

and that works. I must admit, it doesn't really look pretty 😉 my other alternative is to split retrieving the async request data and enhancing the query. that way I can make it non async

Marcel OverdijkOP•4mo ago

I'm now using this:

    const qb = c.var.mydb
      .selectFrom('customer')
      .selectAll('customer');

    const { query } = await this.applyQueryParams(qb)

    const customers = await query.execute();

    const qb = c.var.mydb
      .selectFrom('customer')
      .selectAll('customer');

    const { query } = await this.applyQueryParams(qb)

    const customers = await query.execute();

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Error: don't await SelectQueryBuilder instances directly.