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Topics

TypeScript Basics

Introduction to TypeScriptTypeScript vs JavaScriptSetting up TypeScriptTypeScript Compiler (tsc)tsconfig.json ConfigurationTypeScript in Node.jsTypeScript in the Browser

TypeScript Types

Basic Types in TypeScriptType AnnotationsType InferenceUnion TypesIntersection TypesType AliasesLiteral TypesEnums in TypeScriptAny and Unknown TypesVoid, Null, and UndefinedNever TypeObject Types

TypeScript Variables and Functions

Variable DeclarationsConst AssertionsFunction TypesOptional and Default ParametersRest ParametersFunction OverloadingArrow Functions in TypeScript

TypeScript Interfaces

Interface BasicsOptional PropertiesReadonly PropertiesExtending InterfacesImplementing InterfacesHybrid TypesInterfaces vs Type Aliases

TypeScript Classes

Class BasicsInheritanceAccess ModifiersAbstract ClassesStatic MembersTypeScript ConstructorsGetters and SettersMethod Overriding

Advanced Types

Generics in TypeScriptGeneric ConstraintsConditional TypesMapped TypesIndex TypesTypeScript Utility TypesDiscriminated UnionsIntersection Types

TypeScript Modules

Module BasicsExport and ImportDefault ExportsRe-exportsDynamic ImportsAmbient Modules

TypeScript and OOP

Encapsulation in TypeScriptPolymorphism in TypeScriptTypeScript MixinsDecorators in TypeScript

TypeScript Error Handling

Try-Catch BlocksCustom Error TypesError Handling with Promises

TypeScript and Asynchronous

Promises in TypeScriptAsync/Await in TypeScriptTypeScript Generators

TypeScript Type Manipulation

Keyof OperatorTypeof OperatorIndexed Access TypesConditional TypesInfer KeywordTemplate Literal Types

TypeScript Best Practices

Strict ModeNull CheckingType Assertion Best PracticesTypeScript LintingTypeScript Style Guide

TypeScript and Libraries

Definitely TypedWriting Declaration FilesUsing Third-Party Libraries

TypeScript Tools and Ecosystem

TypeScript PlaygroundTypeScript with VS CodeTypeScript with WebpackTypeScript with ReactTypeScript with AngularTypeScript with Vue

Advanced TypeScript Concepts

TypeScript Compiler APIAbstract Syntax Tree (AST)TypeScript Language ServiceProject ReferencesTypeScript Performance Tuning

TypeScript Interfaces vs Type Aliases

In TypeScript, both interfaces and type aliases provide ways to define custom types. While they share similarities, understanding their differences is crucial for effective TypeScript development.

Interfaces

Interfaces in TypeScript define the structure of objects. They are primarily used for describing the shape of data and can be extended or implemented by classes.

interface Person {
  name: string;
  age: number;
}

const john: Person = { name: "John", age: 30 };

Type Aliases

Type aliases create new names for types. They can represent not just object types, but also primitives, unions, tuples, and other complex types.

type Point = {
  x: number;
  y: number;
};

type ID = string | number;

const point: Point = { x: 10, y: 20 };
const id: ID = "abc123";

Key Differences

  • Declaration Merging: Interfaces support declaration merging, while type aliases do not.
  • Extends and Implements: Interfaces can be extended or implemented by classes, which is not possible with type aliases.
  • Primitive Types: Type aliases can directly represent primitive types, unions, and tuples, which interfaces cannot.
  • Computed Properties: Type aliases can use computed properties, while interfaces cannot.

When to Use Interfaces

Use interfaces when:

  • Defining object shapes that might be extended later
  • Working with classes that need to implement a contract
  • You want to take advantage of declaration merging

When to Use Type Aliases

Use type aliases when:

  • Creating complex types involving unions, intersections, or tuples
  • Defining function types
  • You need to use computed properties

Best Practices

When working with interfaces and type aliases, consider these best practices:

  • Use interfaces for public APIs as they are more extendable
  • Prefer type aliases for complex types or when you need union or intersection types
  • Be consistent in your codebase to improve readability
  • Use type inference when possible to reduce verbosity

Conclusion

Both interfaces and type aliases are powerful features in TypeScript. Understanding their strengths and use cases will help you write more maintainable and expressive code. For more advanced type manipulations, explore conditional types and mapped types.