dart:async library
The dart:async library delivers core capabilities for asynchronous programming in Dart: Future, Stream. Two foundational concepts: Future 1. async / await Recommended by convention; offers better readability compared to .then() …
dart:io
Reference Notice dart:io cannot be used on the Web platform!Supported targets: Dart command-line programs, server-side applications, non-Web Flutter apps (Android/iOS/Windows/macOS/Linux). File & Directory Operations FileSystemEntity is the base class. File …
dart:core Standard Library
dart:core is Dart’s standard core library that gets implicitly imported automatically. It supplies fundamental capabilities required by the language. Below you’ll find core features and sample code grouped by module. …
The dart:convert Library
Learn the core capabilities of the Dart dart:convert library. The dart:convert library provides converters for JSON and UTF-8, and also supports custom converters. JSON: A lightweight text format used to …
The dart:math Library
Dart comes with several built-in libraries that you can leverage to implement various features, including a dedicated library for mathematical operations. Common Constants Trigonometric Functions sin() cos() tan() Parameters: radians. …
Class Modifiers
Control the permissions for external libraries to inherit, implement and instantiate classes, restricting type bodies Modifier order [abstract] [base/interface/final/sealed] [mixin] class; some modifiers are mutually exclusive 1. No modifier Any …
Extension Types
Wrapped at compile time with zero additional runtime objects (zero-cost abstraction); used to assign a new set of static interfaces to existing types and restrict accessible methods. Difference from regular …
Extension methods
Extension methods let you add new functionality to existing types and third-party library types without modifying the source code of the original class. Your IDE’s autocompletion will list extension methods …
Dot shorthands
The .foo dot shorthand syntax lets you omit the type name. As long as the compiler can infer the target type from context, you can write cleaner Dart code. When …
Enums
An enumeration type is a special class used to represent a fixed set of constant values. All enums automatically inherit the Enum class. Enums are sealed types: they cannot be …
Mixins
What Are Mixins A Mixin is a code reuse mechanism that lets you share code across unrelated class inheritance hierarchies. Its core purpose is to inject member implementations into classes …
Class Inheritance and Member Overriding
Extend a class Use the extends keyword to create a subclass derived from a superclass. Use the super keyword to access members (methods, constructors, etc.) defined in the superclass from …
Method
A method is a function that provides behaviors for an object, divided into four categories: instance methods, operator overloading, Getters/Setters, and abstract methods. 1. Instance methods 2. Operators Overloading After …
Primary Constructors
Understand the Concept Minimum Dart language version: 3.13. Purpose: Declare fields + primary constructor in one line at the top of the class, drastically reducing boilerplate code. Its runtime behavior …
Constructor
What is a Constructor A constructor is a special function used to create class instances, typically for initializing properties. Except for the default constructor, all constructors share the same name …
Class
What Are Classes and Objects A class is a category, a classification. It abstracts real-world things into a unified type. For example, we abstract all human beings on Earth into …
Libraries
Every Dart file is inherently a library, even without the library directive; Privacy rule: Identifiers starting with underscore _ are library-private, only visible within the current library, inaccessible across files/libraries; …
Metadata
What are metadata annotations Start with @, attach static metadata information to code. They are read by compilers, IDEs and static analyzers and do not affect runtime logic. Two valid …
Function
In Dart, functions are also objects, which differs slightly from other programming languages. Functions are first-class objects Dart is a fully object-oriented language, and functions themselves are objects with the …
exception error handling
All exceptions in Dart are unchecked exceptions. You don’t need to declare thrown types on functions, and catching errors is not mandatory. There are two core categories: Any non-null object …