one-at-time

Returns action that will be run only one at time.

Install

npm install one-at-time
...
import oneAtTime from 'one-at-time';
// or const oneAtTime = require('one-at-time')
...
const oneAtTimeFetch = oneAtTime(async () => { const { data: res } = await axios.get(url); return res })
...
const response = await oneAtTimeFetch()

Example of usage

const oneAtTime = require("one-at-time");
const wait = ms => new Promise(res => setTimeout(res, ms));
let i = 0;
const hardAction = async () => {
  console.log(`start ${i}`);
  await wait(2000);
  console.log(`end ${i}`);
  return i++;
};

const hardActionOneAtTime = oneAtTime(hardAction);

async function test() {
  const needHardWorkAction = async i => {
    await wait(i * 500);
    // This is hardActionOneAtTime called 10 times, but hardAction - will be executed only 2 times.
    // Because while executing it blocks another executing.
    const res = await hardActionOneAtTime(); 
    // It returns the same result for all calls that was produced while hardAction call executes.
    return res;
  };
  const results = await Promise.all(
    Array.from({ length: 10 }, (e, i) => needHardWorkAction(i))
  );
  console.log(results);
}
test();
// OUTPUT:
// start 0
// end 0
// start 1
// end 1
// [ 0, 0, 0, 0, 0, 1, 1, 1, 1, 1 ]