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.
![Designing for Simplicity]()
Before we get started, it's worth me spending a brief moment introducing myself to you. My name is Mark (or @integralist if Twitter happens to be your communication tool of choice) and I currently work for BBC News in London England as a principal engineer/tech...
![CSS @supports]()
Feature detection via JavaScript is a client side best practice and for all the right reasons, but unfortunately that same functionality hasn't been available within CSS. What we end up doing is repeating the same properties multiple times with each browser prefix. Yuck. Another thing we...
![Smooth Scrolling with MooTools Fx.SmoothScroll]()
I get quite a few support requests for my previous MooTools SmoothScroll article and the issue usually boils down to the fact that SmoothScroll has become Fx.SmoothScroll. Here's a simple usage of Fx.SmoothScroll.
The HTML
The only HTML requirement for Fx.SmoothScroll is that all named...
![Input Incrementer and Decrementer with MooTools]()
Chris Coyier's CSS-Tricks blog is everything mine isn't. Chris' blog is rock star popular, mine is not. Chris prefers jQuery, I prefer MooTools. Chris does posts with practical solutions, I do posts about stupid video-game like effects. If I...
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