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.
![Create a Sheen Logo Effect with CSS]()
I was inspired when I first saw Addy Osmani's original ShineTime blog post. The hover sheen effect is simple but awesome. When I started my blog redesign, I really wanted to use a sheen effect with my logo. Using two HTML elements and...
![Convert XML to JSON with JavaScript]()
If you follow me on Twitter, you know that I've been working on a super top secret mobile application using Appcelerator Titanium. The experience has been great: using JavaScript to create easy to write, easy to test, native mobile apps has been fun. My...
![Create a 3D Panorama Image with A-Frame]()
In the five years I've been at Mozilla I've seen some awesome projects. Some of them very popular, some of them very niche, but none of them has inspired me the way the MozVR team's work with WebVR and A-Frame project have.
A-Frame is a community project...
![Create a Simple News Scroller Using Dojo]()
My journey into Dojo JavaScript has been exciting and I'm continuing to learn more as I port MooTools scripts to Dojo. My latest experiment is porting a simple new scroller from MooTools to Dojo. The code is very similar!
The HTML
The news items...
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