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.
![An Interview with Eric Meyer]()
Your early CSS books were instrumental in pushing my love for front end technologies. What was it about CSS that you fell in love with and drove you to write about it?
At first blush, it was the simplicity of it as compared to the table-and-spacer...
![Send Text Messages with PHP]()
Kids these days, I tell ya. All they care about is the technology. The video games. The bottled water. Oh, and the texting, always the texting. Back in my day, all we had was...OK, I had all of these things too. But I still don't get...
![Use Custom Missing Image Graphics Using MooTools]()
Missing images on your website can make you or your business look completely amateur.
Unfortunately sometimes an image gets deleted or corrupted without your knowledge.
You'd agree with me that IE's default "red x" icon looks awful, so why not use
your own missing image graphic?
The MooTools JavaScript
Note that...
![Checkbox Filtering Using MooTools ElementFilter]()
When I first wrote MooTools ElementFilter, I didn't think much of it. Fast forward eight months later and I've realized I've used the plugin a billion times. Hell, even one of the "big 3" search engines is using it for their maps application.
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