Extract a Number from a String with JavaScript
User input from HTML form fields is generally provided to JavaScript as a string. We've lived with that fact for decades but sometimes developers need to extract numbers from that string. There are multiple ways to get those numbers but let's rely on regular expressions to extract those numbers!
To employ a regular expression to get a number within a string, we can use \d+:
const string = "x12345david";
const [match] = string.match(/(\d+)/);
match; // 12345
Regular expressions are capable of really powerful operations within JavaScript; this practice is one of the easier operations. Converting the number using a Number() wrapper will give you the number as a Number type.
![Camera and Video Control with HTML5]()
Client-side APIs on mobile and desktop devices are quickly providing the same APIs. Of course our mobile devices got access to some of these APIs first, but those APIs are slowly making their way to the desktop. One of those APIs is the getUserMedia API...
![Create Namespaced Classes with MooTools]()
MooTools has always gotten a bit of grief for not inherently using and standardizing namespaced-based JavaScript classes like the Dojo Toolkit does. Many developers create their classes as globals which is generally frowned up. I mostly disagree with that stance, but each to their own. In any event...
![Create a Sexy Persistent Header with Opacity Using MooTools or jQuery]()
I've been working with the Magento eCommerce solution a lot lately and I've taken a liking to a technique they use with the top bar within their administrative control panel. When the user scrolls below a specified threshold, the top bar becomes attached to the...
![Using jQuery and MooTools Together]()
There's yet another reason to master more than one JavaScript library: you can use some of them together! Since MooTools is prototype-based and jQuery is not, jQuery and MooTools may be used together on the same page.
The XHTML and JavaScript
jQuery is namespaced so the...
the code
string.match(/(\d+)/);assumes that a match is found. If no number is present in the string,string.match(/(\d+)/)will return null, and attempting to destructure null will result in an error