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.
![Page Visibility API]()
One event that's always been lacking within the document is a signal for when the user is looking at a given tab, or another tab. When does the user switch off our site to look at something else? When do they come back?
![Camera and Video Control with HTML5]()
Client-side APIs on mobile and desktop devices are quickly providing the same APIs. Of course our mobile devices got access to some of these APIs first, but those APIs are slowly making their way to the desktop. One of those APIs is the getUserMedia API...
![jQuery UI DatePicker: Disable Specified Days]()
One project I'm currently working on requires jQuery. The project also features a datepicker for requesting a visit to their location. jQuery UI's DatePicker plugin was the natural choice and it does a really nice job. One challenge I encountered was the...
![WordPress-Style Comment Controls Using MooTools or jQuery]()
WordPress has a nice little effect on the Admin Dashboard where it shows and hides the comment control links when you mouseover and mouseout of the record's container. Here's how to achieve that effect using MooTools or jQuery.
The XHTML
Notice that we place the links into...
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