Abstract Meta Type Creator

This section show you how to do abstraction with FirelordJS. The example show you how to add updatedAt field to all your update operation.

import {
    MetaTypeCreator,
    DocumentReference,
    AbstractMetaTypeCreator,
    updateDoc,
    ServerTimestamp,
    serverTimestamp,
} from 'firelordjs'

type A = { updatedAt: ServerTimestamp }
type AbstractMetaType = AbstractMetaTypeCreator<A>
type AB = MetaTypeCreator<A & { b: string }, 'AB'>
type AC = MetaTypeCreator<A & { c: boolean }, 'AC'>

type FirestoreUpdateParams<T extends AbstractMetaType> = {
    ref: DocumentReference<T>
    data: Partial<T['writeFlatten']>
}

export function $firestoreUpdate<T extends AbstractMetaType>({
    ref,
    data,
}: FirestoreUpdateParams<T>) {
    const mixin: A = {
        updatedAt: serverTimestamp(),
    }

    // it is not safe enough to type object with spread operator because spread does not trigger excess property check https://stackoverflow.com/questions/59318739/is-there-an-option-to-make-spreading-an-object-strict
    // what you want to do is make sure 'mixin' type is correct
    const mixedData = {
        ...data,
        ...mixin,
    }

    return updateDoc(
        ref,
        //@ts-expect-error
        mixedData
    )
}

const b = 1 as unknown as DocumentReference<AB> // assume this is doc ref
const c = 1 as unknown as DocumentReference<AC> // assume this is doc ref

$firestoreUpdate({
    ref: b,
    data: { b: 'Test' },
})

$firestoreUpdate({
    ref: c,
    data: { c: false },
})