async-paginator's Introduction

paginator

Smart pagination for big collections

Ordered paginator

import { paginator } from 'async-paginator';
const paginate = paginator([1, 2, 3, 4], async (num) => num * 10);
for await (const result of paginate) {
  console.log('Task:', result);
}
// Output will be
/*
Task: 10
Task: 20
Task: 30
Task: 40
*/

Unordered paginator

import { paginatorUnordered } from 'async-paginator';

const sleep = (delay: number) =>
  new Promise<void>((resolve) => setTimeout(resolve, delay));

const paginate = paginatorUnordered([1, 2, 3, 4], async (num) => {
  if (num % 2 === 0) {
    await sleep(10); // timeout 10ms
  }
  return num * 10;
});
for await (const result of paginate) {
  console.log('Task:', result);
}
// Output will be
/*
Task: { data: 10, index: 0 }
Task: { data: 30, index: 2 }
Task: { data: 20, index: 1 }
Task: { data: 40, index: 3 }
*/

Complex example

import { paginatorUnordered } from 'async-paginator';
const sleep = (delay: number) =>
  new Promise<void>((resolve) => setTimeout(resolve, delay));

const paginate = paginatorUnordered(
  [1, 2, 3, 4, 5, 6, 7, 8],
  async (num) => {
    if (num % 2 === 0) {
      await sleep(10); // timeout 10ms
    }
    return num * 10;
  },
  {
    offset: 1,
    chunks: 2,
    mode: 'chunks',
  }
);

const result: number[] = [];

for await (const item of paginate) {
  if (!(item instanceof PaginationAsyncError)) {
    result.push(item.data);
  }
}
console.log("RESULT: ", result);
// RESULT: [30, 20, 50, 40, 70, 60, 80]

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