Gain insights into Dart's object-oriented features, explore extensions, enums, mixins, and asynchronous programming. Discover hands-on code practice to confidently apply Dart in your projects.

dart.tar.gz

dart2_7

Dart is a fully object-oriented, class-based, simple, and clean language. Google’s popular mobile framework, Flutter uses Dart language to implement high-quality native applications, so it’s recommended that you understand Flutter before beginning this course.

In this course, you will dive deep into Dart 2 language features while using interactive hands-on code playgrounds. This course will help you become confident with Dart extensions, enums, mixins, generics, libraries, asynchronous programming, class variables, callable classes, and generator functions.

By the end of this course, you will have a strong understanding of Dart principles, and you’ll be ready to start using this powerful language in your own projects.

Developing Web Applications with Dart

# Introduction

This lesson is an introduction to libraries in Dart/Flutter. A library is a reusable module for frequently used programs/code. It helps to write a modular codebase. In Dart, each app is a library. 

The lesson about libraries is divided into two lessons.

**Dart Libraries #1:** The first lesson covers how to use Dart libraries including the following:

* Using Prefix for library
* Importing specific APIs
* Defer/delay loading library

**Dart Libraries #2:** The second lesson instructs on understanding the following directives:

* The `part` directive
* The `library` directive
* The `export` directive


# Setup

Let's create two libraries `lib1` and `lib2` for demonstration.

## `lib1`

This library has APIs to calculate the sum and difference of two integers.

* **Addition API:** The `int addition(int a, int b)` calculates the sum of two given integers and returns an integer.

* **Subtraction API:** The `int subtraction(int a, int b)` calculates the difference of two given integers and returns an integer.

* **Internal Method-`int _add(int a, int b)`:** It is an internal function/method that performs the real addition. This method is used by the addition API. Identifiers with the underscore (\_) prefix are only available inside the library.

**File 'lib1.dart':**

```dart
int addition(int a, int b) => _add(a, b);

int subtraction(int a, int b) => a - b;

int _add(int a, int b) => a + b;
```

## `lib2`

This library has APIs to check if the given numbers are even or odd.

* **Even number API (`bool isNumberOdd(int num)`):** This API takes a number and returns true if it is even or vice versa.
* **Odd number API (`bool isNumberOdd(int num)`):** This API takes a number and returns true if it is odd or vice versa.

**File 'lib2.dart':**

```dart
bool isNumberOdd(int num) => num.isOdd;

bool isNumberEven(int num) => num.isEven;

//Added to demonstrate handle conflicting name in two different libraries
int addition(int a, int b) => a + b + 2;
```

In this lesson, you will be introduced to the Dart libraries.

Introduction

Dart Extensions

Dart Enums

Dart Mixins

Dart Generics

Dart Libraries

Asynchronous Programming In Dart

Miscellaneous

Next Steps

Dart Libraries #1

Introduction

Setup

`lib1`