How to extract the return type from a Query instance?

I'm trying to extract the result type from a Query instance for use with generics and type inference.

The documentation mentions

GetResult

GetResult

: https://tanstack.com/db/latest/docs/reference/type-aliases/GetResult

However, GetResult expects a Context type parameter, not a Query:

type Result = GetResult<typeof myQuery>

type Result = GetResult<typeof myQuery>

Example use case

export const myQuery = new Query()
  .from({ collection1 })
  .join(// Any join...)
  .select(({ ... }) => {
    const transformed = // any data transformation...
    return transformed
  })

// How do I extract this type?
export type MyQueryResult = ???

export const myQuery = new Query()
  .from({ collection1 })
  .join(// Any join...)
  .select(({ ... }) => {
    const transformed = // any data transformation...
    return transformed
  })

// How do I extract this type?
export type MyQueryResult = ???

ExtractContext

ExtractContext

exists in the library but isn't exported, which would solve this:

type MyContext = ExtractContext<typeof myQuery>
type Result = GetResult<MyContext>

type MyContext = ExtractContext<typeof myQuery>
type Result = GetResult<MyContext>

Questions:
1. Should

ExtractContext

ExtractContext

be exported to enable this pattern?
2. Or is there a recommended alternative approach for extracting query result types?

Thanks

TanStack•3mo ago•

3 replies

dramatic-maroon

How to extract the return type from a Query instance?

I'm trying to extract the result type from a Query instance for use with generics and type inference.

The documentation mentions

GetResult

GetResult

: https://tanstack.com/db/latest/docs/reference/type-aliases/GetResult

However, GetResult expects a Context type parameter, not a Query:

type Result = GetResult<typeof myQuery>

type Result = GetResult<typeof myQuery>

Example use case

export const myQuery = new Query()
  .from({ collection1 })
  .join(// Any join...)
  .select(({ ... }) => {
    const transformed = // any data transformation...
    return transformed
  })

// How do I extract this type?
export type MyQueryResult = ???

export const myQuery = new Query()
  .from({ collection1 })
  .join(// Any join...)
  .select(({ ... }) => {
    const transformed = // any data transformation...
    return transformed
  })

// How do I extract this type?
export type MyQueryResult = ???

ExtractContext

ExtractContext

exists in the library but isn't exported, which would solve this:

type MyContext = ExtractContext<typeof myQuery>
type Result = GetResult<MyContext>

type MyContext = ExtractContext<typeof myQuery>
type Result = GetResult<MyContext>

Questions:
1. Should

ExtractContext

ExtractContext

be exported to enable this pattern?
2. Or is there a recommended alternative approach for extracting query result types?

Thanks

How to extract the return type from a Query instance?

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