All files PaginationStream.ts

94.11% Statements 32/34
94.44% Branches 17/18
100% Functions 3/3
94.11% Lines 32/34

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 551x                     1x 1x   7x   7x   7x   7x   1x 7x 7x 7x   1x 4358x 4115x 4115x 4115x 4115x   4358x 6x 6x 6x   237x 237x 559x 235x 235x   236x 236x   236x 4358x     4358x 1x  
import { Readable } from 'node:stream'
import type { PaginationList, PaginationListWithCount } from './apiTypes.ts'
 
type FetchPage<T> = (
  pageno: number,
) =>
  | PaginationList<T>
  | PromiseLike<PaginationList<T>>
  | PaginationListWithCount<T>
  | PromiseLike<PaginationListWithCount<T>>
 
export default class PaginationStream<T> extends Readable {
  private _fetchPage: FetchPage<T>
 
  private _nitems?: number
 
  private _pageno = 0
 
  private _items: T[] = []
 
  private _itemsRead = 0
 
  constructor(fetchPage: FetchPage<T>) {
    super({ objectMode: true })
    this._fetchPage = fetchPage
  }
 
  override async _read() {
    if (this._items.length > 0) {
      this._itemsRead++
      process.nextTick(() => this.push(this._items.pop()))
      return
    }
 
    if (this._nitems != null && this._itemsRead >= this._nitems) {
      process.nextTick(() => this.push(null))
      return
    }
 
    try {
      const { items, ...rest } = await this._fetchPage(++this._pageno)
      if ('count' in rest) {
        this._nitems = rest.count
      }
 
      this._items = Array.from(items)
      this._items.reverse()
 
      this._read()
    } catch (err) {
      this.emit('error', err)
    }
  }
}