const TimeQueue = require('timequeue');

const worker = (arg1, arg2, callback) => {
  someAsyncFunction(calculation(arg1, arg2), callback);
};

// Worker can be an async function.
const worker = async (arg1) => {
  let result1 = await anotherSyncFunction(arg1);
  return andAnotherOne(result1);
};

// create a queue with max 5 concurrency every second
let q = new TimeQueue(worker, { concurrency: 5, every: 1000 });

// Push tasks onto the queue.
q.push(42, 24);
q.push(2, 74);

// Optional callback when pushing tasks.
q.push(2, 2, (err, result) => {
  // task finished
});

// Can use promise/await syntax instead.
let result = await q.push(3, 5);

{
  // Maximum tasks to execute concurrently.
  concurrency: 1

  // How much time in milliseconds to allow no more than
  // the max number of concurrent tasks to run.
  // If the max amount of concurrent tasks finish faster than this time limit,
  // additional tasks will wait until enough time has passed before starting.
, every: 0

  // Maximum number of tasks to keep in the queue.
  // While full, pushed tasks will be ignored.
, maxQueued: Infinity

  // If set, tasks will error if they take too much time.
  // if callback was given to that task, it will be called with the error,
  // otherwise, the returned promise should be `caught`.
, timeout: 0

  // You can pass a custom store to share tasks between several queues.
  // Default is MemoryStore from `src/mem-store.ts`.
  // Look at `example/redis-store.ts` for an example that saves tasks onto redis.
, store: MemoryStore
}