Today I learnt about dart's extension method which you can use to extend any class, (even custom classes) to prevent writing lots of boilerplate code.

to be fair, i don't see myself really writing any custom extension methods anytime soon but i thought it would be nice to have my own in-house point of reference.

If you are here and you are not me (well because i read my notes everytime when I feel the urge to doomscroll),

this video offers a better visual lesson that this note ever will.

Working with an extension method would look something like this

extension Name on Class {

bool get isName {

return something

}
}

How you would use this depends on the use case. but before we go there, here is a simpler real world example of where this might work, for email validation:

extension EmailValidation on String {
bool get isEmail {
   final regex = RegExp(r'^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$');
   return regex.hasMatch(this)
}
}

Then use it like this:

import your helper uptop

final isValid = emailInput.isEmail;

TextField(
  decoration: InputDecoration(
    hintText: 'Email',
    focusedBorder: OutlineInputBorder(
      borderSide: BorderSide(
        color: emailInput.isEmail ? Colors.green : Colors.red,
      ),
    ),
  ),
);

This line:

color: emailInput.isEmail ? Colors.green : Colors.red,

Saves us from doing this each time we want to check an input:

final isValid = RegExp(r'^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$').hasMatch(emailInput);

TextField(
decoration: InputDecoration(
hintText: 'Email',
focusedBorder: OutlineInputBorder(
borderSide: BorderSide(
color: RegExp(r'^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$')
.hasMatch(emailInput)
? Colors.green
: Colors.red,
),
),
),
);