Dart is a multi-paradigm programming language developed by Google. It can be compiled to native ARM/x86 machine code (either Ahead-Of-Time or Just-In-Time) as well as to JavaScript. Its most notable use case is developing cross-platform mobile apps with Flutter. In this tutorial, I will introduce the basics of the language, as well as provide resources for further research. Some basic knowledge of another programming language (JS/C/Python/etc) is expected.

Try it out yourself

You can try writing Dart code directly in your browser on this website. But note that it does not support all features, for example, user input. Alternatively, you can install Dart SDK, and run dart filename.dart in the terminal to launch your code.

Hello World

Dart uses syntax similar to C to define functions. Every app has an entry point – the main() function. You can print out messages using print() function. See this example:

Variables

You can use either strong or dynamic types in Dart. Strong means you have to choose variable type at declaration time and it does not change, but with dynamic typing, it can hold values of any type. By default, all variables a strongly typed, even if you do not write any specific type. To make them dynamic, dynamic keyword is used. Look at the following example:

The basic types of variables in Dart are: int, double, bool, String, List, Set, Map, Runes and Symbol.

Control Flow

You can use the same control flow structures you have seen in many other languages, such as if, for, while:

Control flow statements such as continue, break, switch and case are also supported.

Comments

Comments in Dart work exactly like in C or JS:

Imports

Dart supports importing libraries and .dart files using the import statement:

Dart also supports something called deferred imports. These imports are loaded on demand: you may want to use them when you do not always have to use a certain library:

Classes

Dart supports classes and most of the OOP paradigms. Here is a sample definition of a class:

You can implement inheritance using the extends keyword. Keep in mind that a class can only inherit one class, multiple inheritance is not supported.

To simply reuse some common code without the overhead of inheritance, you can use mixins. You create a mixin and later attach it to classes using with keyword. Consider this example:

Instead of interfaces, Dart uses inheritance. All classes implicitly define an interface so it is sufficient to inherit the class:

You can define abstract classes with the abstract keyword and they work pretty much like you expect:

async/await

This is a complex topic, and if you are not familiar with async/await syntax I suggest you read this article first. async/await work in Dart pretty much the same way they do in JavaScript:

Future is Dart’s version of JS Promises, by the way.

I hope you find this tutorial useful. If you want to learn more, Dart’s documentation is a good place to start.