In general using child processes and running multiple node applications as separate processes together with a load balancer or shared data storage (like redis) is important for scaling your code. This should be neglible and if it matters you need to seriously consider what your trying to do, why you need such accuracy and what kind of real time alternative hardware is available to do the job instead. This way even if some long blocking code is running in your main process your child process has already started itself and placed a setTimeout in a new process and a new thread and will thus run when you expect it to.įurther complication are at a hardware level where you have more threads running then processes and thus context switching will cause (very minor) delays from your expected timing. ![]() Use the child process module to spawn a new node.js program that does your logic and pass data to that process through some kind of a stream (maybe tcp). This document talks about various queues concerning EventLoop to better understand how best to use Promises, Timers (setTimeout etc) V8 Engine works. The only way to ensure code is executed is to place your setTimeout logic in a different process. Eventloop in NodeJS: MacroTasks and MicroTasks. Remove the loop and you'll see it's 500 on the nose. Cancel interval timer : To cancel one interval timer or a timer created by setInterval, the below method is used : clearInterval(obj) Here, obj is a Timeout object returned by the setInterval method. Unless the interpreter optimises the loop away (which it doesn't on chrome), you'll get something in the thousands. Poll - accepts incoming connections and data processing. Pending callbacks - executes any callbacks that are ready to run. fiddle with the number of iterations depending on how quick your machine is The Event Loop has the following basic stages: Timers - executes callbacks that have been scheduled with setTimeout and setInterval. Consider this example: setTimeout(function (), 500) The setTimeout function is found in the Timers module of Node.js. The delay of the called function begins after the remaining statements in the script have finished executing. The Node.js setTimeout method can be used at various places in javascript code where user need some operation to be performed after a delay of time. Return Value: This method returns nothing but a call back function for further operation. The setTimeout function is used to call a function after the specified number of milliseconds. The reason for this is that there is no preemption of JavaScript by JavaScript. Syntax: tTimeout ( msecs, callback) Parameters: This method takes the socket time out value in a millisecond. Like the master process and a number of worker process concepts in Nginx, Node. ![]() It is highly inspired by the high concurrency model design of the Nginx web server. In Node, this is 1ms, but in browsers it can be as much as 50ms. Node.js is an asynchronous, non-blocking, and event-driven architecture. Furthermore, passing 0, a non-number, or a negative number, will cause it to wait a minimum number of ms. The semantics of setTimeout are roughly the same as in a web browser: the timeout arg is a minimum number of ms to wait before executing, not a guarantee.
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