From 04ee60671b4599d2c1b7b5f011a0e1731d11f1ed Mon Sep 17 00:00:00 2001 From: Chalarangelo Date: Sat, 6 Nov 2021 20:32:38 +0200 Subject: [PATCH] Add JS sync vs async question --- blog_posts/javascript-sync-async.md | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 blog_posts/javascript-sync-async.md diff --git a/blog_posts/javascript-sync-async.md b/blog_posts/javascript-sync-async.md new file mode 100644 index 000000000..1b7096c9a --- /dev/null +++ b/blog_posts/javascript-sync-async.md @@ -0,0 +1,29 @@ +--- +title: What is the difference between synchronous and asynchronous code in JavaScript? +type: question +tags: javascript,function,promise +authors: chalarangelo +cover: blog_images/pineapple-on-green.jpg +excerpt: Understanding the differences between synchronous and asynchronous code is a crucial piece of knowledge for every web developer. +firstSeen: 2021-11-14T05:00:00-04:00 +--- + +Synchronous code runs in sequence. This means that each operation must wait for the previous one to complete before executing. + +```js +console.log('One'); +console.log('Two'); +console.log('Three'); +// LOGS: 'One', 'Two', 'Three' +``` + +Asynchronous code runs in parallel. This means that an operation can occur while another one is still being processed. + +```js +console.log('One'); +setTimeout(() => console.log('Two'), 100); +console.log('Three'); +// LOGS: 'One', 'Three', 'Two' +``` + +Asynchronous code execution is often preferable in situations where execution can be blocked indefinitely. Some examples of this are network requests, long-running calculations, file system operations etc. Using asynchronous code in the browser ensures the page remains responsive and the user experience is mostly unaffected.