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.
![Facebook Open Graph META Tags]()
It's no secret that Facebook has become a major traffic driver for all types of websites. Nowadays even large corporations steer consumers toward their Facebook pages instead of the corporate websites directly. And of course there are Facebook "Like" and "Recommend" widgets on every website. One...
![Detect DOM Node Insertions with JavaScript and CSS Animations]()
I work with an awesome cast of developers at Mozilla, and one of them in Daniel Buchner. Daniel's shared with me an awesome strategy for detecting when nodes have been injected into a parent node without using the deprecated DOM Events API.
![Create a Trailing Mouse Cursor Effect Using MooTools]()
Remember the old days of DHTML and effects that were an achievement to create but had absolutely no value? Well, a trailing mouse cursor script is sorta like that. And I'm sorta the type of guy that creates effects just because I can.
![MooTools Fun with Fx.Shake]()
Adding movement to your website is a great way to attract attention to specific elements that you want users to notice. Of course you could use Flash or an animated GIF to achieve the movement effect but graphics can be difficult to maintain. Enter...
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