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.
![5 HTML5 APIs You Didn’t Know Existed]()
When you say or read "HTML5", you half expect exotic dancers and unicorns to walk into the room to the tune of "I'm Sexy and I Know It." Can you blame us though? We watched the fundamental APIs stagnate for so long that a basic feature...
![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...
![Introducing MooTools ElementSpy]()
One part of MooTools I love is the ease of implementing events within classes. Just add Events to your Implements array and you can fire events anywhere you want -- these events are extremely helpful. ScrollSpy and many other popular MooTools plugins would...
![CSS Tooltips]()
We all know that you can make shapes with CSS and a single HTML element, as I've covered in my CSS Triangles and CSS Circles posts. Triangles and circles are fairly simply though, so as CSS advances, we need to stretch the boundaries...
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