If you need a large delay, there’s a chance that it may even crash things altogether. Maybe this code does exactly what you’re hoping for, but be aware that it has a large disadvantage: the loop will block JavaScript’s execution thread and ensure that nobody can interact with your program until it finishes. How to Write Better Sleep Function in JavaScript The loop will keep going while the difference between date and currentDate is less than the desired delay in milliseconds. In the loop it repeatedly gets the number of milliseconds which have elapsed since Januand assigns the value to the previously declared currentDate variable. It then creates an empty currentDate variable, before entering a do. It works by using the Date.now method to get the number of milliseconds that have elapsed since Januand assigning that value to a date variable. log ( 'World!' ) Īs expected, this will log “Hello”, pause for two seconds, then log “World!” log ( 'Hello' ) setTimeout ( ( ) => console. The standard way of creating a delay in JavaScript is to use its setTimeout method. I was wondering if there's a trick around this I'm trying to accomplish the following. Unfortunately, as I understand the sleep() function in PHP delays the whole script. Now that we have a better understanding of JavaScript’s execution model, let’s have a look at how JavaScript handles delays and asynchronous code. I'm trying to insert delays between echo commands and wanted to use the sleep() function. How to Use SetTimeout in JavaScript Properly If any of this is news to you, you should watch this excellent conference talk: What the heck is the event loop anyway? Rather, it will continue on its way, output “Hello!” to the console, and then when the request returns a couple of hundred milliseconds later, it will output the number of repos. It will not, however, wait for the request to complete. The JavaScript interpreter will encounter the fetch command and dispatch the request. This is because fetching data from an API is an asynchronous operation in JavaScript. If you run this code, it will output “Hello!” to the screen, then the number of public repos attributed to my GitHub account. Execution goes from top to bottom.Ĭontrast that with the equivalent JavaScript version: fetch ( '' ). It then parses the response, outputs the number of public repos attributed to my GitHub account and finally prints “Hello!” to the screen. run cron job only when machine is idle (linux) 1. Execute a PHP cron every 5 minutes but put a function to sleep to run after 15 minutes. get (uri ) )Īs one might expect, this code makes a request to the GitHub API to fetch my user data. How to make a script launched by cron to sleep for X seconds 2. Understanding this is crucial for effectively managing time and asynchronous operations in your code.Ĭonsider the following Ruby code: require 'net/http' require 'json' Now that we’ve got a quick solution under our belts, let’s delve into the mechanics of JavaScript’s execution model. Note: In order to delay program execution for a fraction of a second, use usleep () as the sleep () function expects an int. Understanding JavaScript’s Execution Model Delays the program execution for the given number of seconds.
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