How to sleep the thread in node.js without affecting other threads?

Question

As per Understanding the node.js event loop, node.js supports a single thread model. That means if I make multiple requests to a node.js server, it won't spawn a new thread for each request but will execute each request one by one. It means if I do the following for the first request in my node.js code, and meanwhile a new request comes in on node, the second request has to wait until the first request completes, including 5 second sleep time. Right?

var sleep = require('sleep');     sleep.sleep(5)//sleep for 5 seconds 

Is there a way that node.js can spawn a new thread for each request so that the second request does not have to wait for the first request to complete, or can I call sleep on specific thread only?

Answer 1

If you are referring to the npm module sleep, it notes in the readme that sleep will block execution. So you are right - it isn't what you want. Instead you want to use setTimeout which is non-blocking. Here is an example:

setTimeout(function() {   console.log('hello world!'); }, 5000); 

---

For anyone looking to do this using es7 async/await, this example should help:

const snooze = ms => new Promise(resolve => setTimeout(resolve, ms));  const example = async () => {   console.log('About to snooze without halting the event loop...');   await snooze(1000);   console.log('done!'); };  example(); 

Answer 2

In case you have a loop with an async request in each one and you want a certain time between each request you can use this code:

   var startTimeout = function(timeout, i){         setTimeout(function() {             myAsyncFunc(i).then(function(data){                 console.log(data);             })         }, timeout);    }     var myFunc = function(){         timeout = 0;         i = 0;         while(i < 10){             // By calling a function, the i-value is going to be 1.. 10 and not always 10             startTimeout(timeout, i);             // Increase timeout by 1 sec after each call             timeout += 1000;             i++;         }     } 

This examples waits 1 second after each request before sending the next one.