Novice JavaScript developers need to know that the "not not" operator is using implicitly the original loose comparison method instead of the exact === or !== operators and also the hidden cast …

Learn how to use JavaScript to hide or show elements on a webpage effectively.

Related to Is there a "null coalescing" operator in JavaScript? - JavaScript now has a ?? operator which I see in use more frequently. Previously most JavaScript code used ||. let userAge =

A valid JavaScript identifier shuold must start with a letter, underscore (_), or dollar sign ($); subsequent characters can also be digits (0-9). Because JavaScript is case sensitive, letters include the …

What is the most efficient way to groupby objects in an array? For example, given this array of objects:

In all other cases, you're safe to use ==. Not only is it safe, but in many cases it simplifies your code in a way that improves readability. I still recommend Crockford's talk for developers who don't want to …

Dec 11, 2008 · I'm using JSLint to go through JavaScript, and it's returning many suggestions to replace == (two equals signs) with === (three equals signs) when doing things like comparing …

Note: In general, extending the built-in prototypes in JavaScript is generally not recommended. I am providing as extensions on the String prototype simply for purposes of illustration, showing different …

9 Use RegEx for string match or comparison. In JavaScript, you can use match() for string comparison, don't forget to put i in the regular expression. This flag will force case insensitive testing. Example: To …

This function below doesn’t work like I want it to; being a JS novice I can’t figure out why. I need it to wait 5 seconds before checking whether the newState is -1. Currently, it doesn’t wait, i...