One of the biggest development boosts is having a decent boilerplate code base you can use when starting new projects. One way to encourage re-use of code is the use of .NET extension methods. I like them so much, me and Fons Sonnemans made a website dedicated to them. My favorite methods are Chris Meijers IsFilled() and IsEmpty(). I use them all the time to avoid checking for !String.IsNullOrEmpty() which is a lot harder to read.
I am currently working on a HTML5 website that uses KnockoutJS, jQuery and a bit of MVC3 and need to check if a string has a value. I know Javascript should just support:
if (value) { // you are here if value != null and value.length>0 } but for some reason it did not work for me in combination with a Knockout Observable so I created a function that returns true when the string is filled. Then I wondered if Javascript has support for extension methods. And it has!
The following code is a js file (/ExtensionMethods/String.js) that you can include in your project:
String.prototype.IsFilled = function () { if (this && this.length > 0) { return true; } return false; } String.prototype.IsEmpty = function () { return !this.IsFilled(); } Include and use the extensionmethod like this: <!DOCTYPE html> <html> <head> <title>Javascript ExtensionMethods</title> <script src="Extensionmethods/String.js"></script> <script type="text/javascript"> //<![CDATA[ var name="Loek van den Ouweland"; document.write("name.IsFilled(): "+name.IsFilled()); document.write("<br/>"); document.write("name.IsEmpty(): "+name.IsEmpty()); //```> </script> </head> <body> <h1>ExtensionMethods in Javascript</h1> <h2><a href="http://loekvandenouweland.com/">http://loekvandenouweland.com/</a></h2> </body> </html>