Use of Dart extension Methods in existing APIs Class.

Extension Methods:

In this blog, we will check the use of Dart Extension methods in the flutter. Extension methods were introduced in Dart 2.7.

Sometimes we need additional functionalities which do not provide in existing libraries. We can add our own functionality by using the extension in the existing class of libraries’ APIs

Extension methods used to add additional functionality to existing libraries’ APIs. We can define extension with methods, getters, setters, and operators.

Read more about Flutter app development.

Extension Syntax:

extension <extension name> on <type> { 
(<member definition>)* 
}

extension <extension name> on <type> {

(<member definition>)*

}

Extension On String Class:

Let’s check some String Class extension examples.

extension StringExtension on String {

  bool get isNullOrEmpty {
    return this == null || this.isEmpty;
  }

  bool get isNotNullOrEmpty {
    return !(this == null || this.isEmpty);
  }

  get firstLetterToUpperCase {
    if (this != null)
      return this[0].toUpperCase() + this.substring(1);
    else
      return null;
  }

  get removeAllHtmlTags {
    if (this != null) {
      RegExp exp = RegExp(r"<[^>]*>", multiLine: true, caseSensitive: true);
      return this.replaceAll(exp, '');
    }
    else
      return null;
  }

}

extension StringExtension on String {

bool get isNullOrEmpty {

return this == null || this.isEmpty;

}

bool get isNotNullOrEmpty {

return !(this == null || this.isEmpty);

}

get firstLetterToUpperCase {

if (this != null)

return this[0].toUpperCase() + this.substring(1);

else

return null;

}

get removeAllHtmlTags {

if (this != null) {

RegExp exp = RegExp(r"<[^>]*>", multiLine: true, caseSensitive: true);

return this.replaceAll(exp, '');

}

else

return null;

}

Extension On List Class:

Let’s check some List Class extension examples.

extension ListExtension on List {
  bool get isNullOrEmpty {
    return this == null || this.isEmpty;
  }
}

extension ListExtension on List {

bool get isNullOrEmpty {

return this == null || this.isEmpty;

}

Using Extension methods:

You need to just import your extensions methods class and call Extention getter using dot(.) on variable

///Let's remove HTML tags from String

   String withoutHtmlTags = "String Contains Html Tags".removeAllHtmlTags;

   String fistLetterWithUpperCase = "String with lower case".firstLetterToUpperCase;

///Let's remove HTML tags from String

String withoutHtmlTags = "String Contains Html Tags".removeAllHtmlTags;

String fistLetterWithUpperCase = "String with lower case".firstLetterToUpperCase;

I hope this blog will help to add some utility functionality to existing APIs.

Happy Learning 🙂

Reference Links:https://dart.dev/guides/language/extension-methods

yogendra singh 28 April 2023

. . .

Flutter: Use of Dart extension Methods.

Extension Methods:

Extension Syntax:

Extension On String Class:

Extension On List Class:

Using Extension methods:

Leave a Comment Cancel Reply

Flutter: Use of Dart extension Methods.

Extension Methods:

Extension Syntax:

Extension On String Class:

Extension On List Class:

Using Extension methods:

Leave a Comment Cancel Reply

Message Sent!