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RobertS

•Created by RobertS on 5/8/2024 in #help

Pagination proper TypeScript return types generics

Hi, I am having some hard time during implementation of basic pagination function. I wanted to make it as generic as possible but not able to get to the point where I will be able to access specific property from a specific model. Below is some basic code snippet which I am trying to implement

export type PaginationResult<T> = {
    data: T
    page: number
    pageSize: number
}

export class MyRepository extends BaseRepository<typeof users> {
    constructor() {
        super(users)
    }

    async findAll() {
        const users = await super.findAll()
        users.data[0] // no proper suggestion here
        return users
    }
}

@Injectable()
export class BaseRepository<T extends PgTable> {
    constructor(protected readonly schema: T) {}

    async findAll() {
        const query = db.select().from(this.schema).where(eq(this.schema.id, 1))
        const dynamicQuery = query.$dynamic()
        return await this.withPagination(dynamicQuery, 1)
    }

    async withPagination<T extends PgSelect>(
        qb: T,
        orderByColumn: PgColumn | SQL | SQL.Aliased,
        page = 1,
        pageSize = 3,
    ) {
        const data = await qb
            .orderBy(orderByColumn)
            .limit(pageSize)
            .offset((page - 1) * pageSize)

        return {
            data,
            page,
            pageSize,
            totalCount: 1000,
        }
    }
}

export type PaginationResult<T> = {
    data: T
    page: number
    pageSize: number
}

export class MyRepository extends BaseRepository<typeof users> {
    constructor() {
        super(users)
    }

    async findAll() {
        const users = await super.findAll()
        users.data[0] // no proper suggestion here
        return users
    }
}

@Injectable()
export class BaseRepository<T extends PgTable> {
    constructor(protected readonly schema: T) {}

    async findAll() {
        const query = db.select().from(this.schema).where(eq(this.schema.id, 1))
        const dynamicQuery = query.$dynamic()
        return await this.withPagination(dynamicQuery, 1)
    }

    async withPagination<T extends PgSelect>(
        qb: T,
        orderByColumn: PgColumn | SQL | SQL.Aliased,
        page = 1,
        pageSize = 3,
    ) {
        const data = await qb
            .orderBy(orderByColumn)
            .limit(pageSize)
            .offset((page - 1) * pageSize)

        return {
            data,
            page,
            pageSize,
            totalCount: 1000,
        }
    }
}

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