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 Spinning Rays with CSS3: Revisited]()
![Serving Fonts from CDN]()
For maximum performance, we all know we must put our assets on CDN (another domain). Along with those assets are custom web fonts. Unfortunately custom web fonts via CDN (or any cross-domain font request) don't work in Firefox or Internet Explorer (correctly so, by spec) though...
![MooTools Equal Heights Plugin: Equalizer]()
Keeping equal heights between elements within the same container can be hugely important for the sake of a pretty page. Unfortunately sometimes keeping columns the same height can't be done with CSS -- you need a little help from your JavaScript friends. Well...now you're...
![Introducing MooTools LinkAlert]()
One of my favorite Firefox plugins is called LinkAlert. LinkAlert shows the user an icon when they hover over a special link, like a link to a Microsoft Word DOC or a PDF file. I love that warning because I hate the surprise...
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