Dart is an object-oriented programming language, and it supports all the concepts of object-oriented programming such as classes, object, inheritance, mixin, and abstract classes. As the name suggests, it focuses on the object and objects are the real-life entities.
Use dart pad to run dart code. Dart Pad. You can also install dart in your system too. Install Dart link
In data you can pass data two ways.
In Flutter we have @required which will show warning if data is not passed. We can make it show error if data is not passed by added this file to root of your flutter project. You can tweak dart behaviours like this too. file