Drizzle Team•13mo ago

how to encapsulate a general pagination function

I am looking to create a generalized pagination function to simplify the implementation of APIs with pagination capabilities. Here's the code I'm currently using:

// api route
const routes = {
  list: async (page: number, size: number) => {
    // ...
    const query = db.select()
      .from(billings)
      .orderBy(desc(billings.transactionAt))
    const dynamicQuery = query.$dynamic()
    const res = await withPagination(dynamicQuery, page, size)
    return res
  }
}

const withPagination = (
  query: PgSelect,
  page: number,
  size: number
) => {
  const all = await query
  const count = all.length
  const currentTailIndex = page * size
  const currentHeadIndex = currentTailIndex - size
  const meta: PageMeta = {
    currentPage: page,
    isFirstPage: page === 1,
    isLastPage: currentTailIndex >= count,
    previousPage: page - 1 === 0 ? null : page - 1,
    nextPage: currentTailIndex >= count ? null : page + 1,
    pageCount: Math.ceil(count / size),
  }

  const res = all.slice(currentHeadIndex, size)
  return {
    ...meta,
    data: res,
  }
}

// api route
const routes = {
  list: async (page: number, size: number) => {
    // ...
    const query = db.select()
      .from(billings)
      .orderBy(desc(billings.transactionAt))
    const dynamicQuery = query.$dynamic()
    const res = await withPagination(dynamicQuery, page, size)
    return res
  }
}

const withPagination = (
  query: PgSelect,
  page: number,
  size: number
) => {
  const all = await query
  const count = all.length
  const currentTailIndex = page * size
  const currentHeadIndex = currentTailIndex - size
  const meta: PageMeta = {
    currentPage: page,
    isFirstPage: page === 1,
    isLastPage: currentTailIndex >= count,
    previousPage: page - 1 === 0 ? null : page - 1,
    nextPage: currentTailIndex >= count ? null : page + 1,
    pageCount: Math.ceil(count / size),
  }

  const res = all.slice(currentHeadIndex, size)
  return {
    ...meta,
    data: res,
  }
}

However, I'm encountering an issue where the type of res is lost. Is there a way to ensure that the result maintains the original table column types?

1 Reply

Angelelz•13mo ago

Yes, you should make the withPagination function generic over the query. Like the example in the docs

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how to encapsulate a general pagination function