distributed debounce function using redis

distributed-debounce-function.ts

import redis from "redis";
const redisclient = redis.createClient();

async function distributedDebounce(callback: () => void, args: { ttl: number, key: string }) {
  // update ttl.
  await new Promise((resolve, reject) => {
    redisclient.set(args.key, '', 'PX', args.ttl, (error, result) => {
      if (error) return reject(error);
      else return resolve(result);
    })
  });
  // wait for ttl sec.
  await wait(args.ttl);
  // if key does not exists, then call callback.
  const isExists = await new Promise<number>((resolve, reject) => {
    redisclient.exists(args.key, (error, result) => {
      if (error) return reject(error);
      else return resolve(result);
    });
  });
  if (isExists === 1) return;
  // lock for atomicity
  const ok = await new Promise<'OK' | null>((resolve, reject) => {
    redisclient.set(`${args.key}_lock`, '', 'NX', 'PX', 100, (error, result) => {
      if (error) return reject(error);
      else return resolve(result);
    });
  });
  if (!ok) return;
  callback();
}