SohaibRaza / limit-concurrency

Running Examples

1. yarn install
2. yarn build
3. open examples/index.html
4. Enter urls
5. Enter concurrency limit
6. Click fetch

---

Example 1:

import limitConcurrency from "limit-concurrency";

async function getUsers() {
  const result = await limitConcurrency({
    collection: [
      "https://jsonplaceholder.ir/users/1",
      "https://jsonplaceholder.ir/users/2",
      "https://jsonplaceholder.ir/users/3",
      "https://jsonplaceholder.ir/users/4",
      "https://jsonplaceholder.ir/users/5",
    ],
    asyncTask: async (url) => {
      const response = await fetch(url);
      const text = await response.text();
      return text;
    },
    limit: 2, // only fetch two pages at a time
  });

  console.log(result);
}

Example 2:

import limitConcurrency from "limit-concurrency";
import axios from "axios";

async function getTODOs() {
  const result = await limitConcurrency({
    collection: [1, 2, 3, 4, 5, 6, 7, 8, 9],
    asyncTask: async (id) => {
      const response = await axios.get(`https://jsonplaceholder.typicode.com/todos/${id}`);
      return response.data;
    },
    limit: 4, // only fetch four tasks at a time
  });

  console.log(result);
}

Test Cases

• ✓ runs every item in a collection through an async function limiting the number of concurrent workers.
• ✓ works with max limit greater than one.
• ✓ works with an empty collection.
• ✓ returns the collection in input order .
• ✓ defaults to a Promise.all implements if no max limit is given.
• ✓ throws at the first error.
• ✓ throws if the last item throws.
• ✓ does not mutate the collection.

#promises #concurrency #async #javascript #queue-promise #es6-promise #promise-pool #limit-promise