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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

Async/Await in TypeScript

Async/await is a powerful feature in TypeScript for handling asynchronous operations. It provides a more intuitive and readable way to work with Promises, making asynchronous code look and behave like synchronous code.

Understanding Async/Await

The async keyword is used to define an asynchronous function. These functions always return a Promise. The await keyword can only be used inside an async function and allows you to wait for a Promise to resolve before continuing execution.

Basic Syntax


async function fetchData(): Promise<string> {
    const response = await fetch('https://api.example.com/data');
    const data = await response.json();
    return data;
}

In this example, fetchData is an async function that returns a Promise resolving to a string. The await keyword is used to wait for the fetch operation and JSON parsing to complete.

Error Handling

Async/await makes error handling more straightforward. You can use traditional try/catch blocks to handle errors in asynchronous code:


async function fetchData(): Promise<string> {
    try {
        const response = await fetch('https://api.example.com/data');
        const data = await response.json();
        return data;
    } catch (error) {
        console.error('Error fetching data:', error);
        throw error;
    }
}

Using with Promise.all()

Async/await can be combined with Promise.all() for concurrent operations:


async function fetchMultipleData(): Promise<string[]> {
    const [data1, data2] = await Promise.all([
        fetch('https://api.example.com/data1').then(res => res.json()),
        fetch('https://api.example.com/data2').then(res => res.json())
    ]);
    return [data1, data2];
}

Best Practices

  • Always handle errors using try/catch or attaching a .catch() to the returned Promise.
  • Use Promise.all() for concurrent operations to improve performance.
  • Avoid mixing callbacks and async/await in the same function.
  • Remember that async functions always return a Promise, even if you don't explicitly return one.

Considerations

While async/await simplifies asynchronous code, it's important to understand the underlying Promise mechanics. This knowledge is crucial for advanced error handling and complex asynchronous flows.

Async/await is particularly useful when working with APIs, file operations, and database queries in TypeScript. It integrates well with TypeScript in Node.js environments and modern front-end frameworks.

Conclusion

Async/await in TypeScript offers a clean and efficient way to handle asynchronous operations. By mastering this feature, developers can write more readable and maintainable asynchronous code, leading to improved productivity and fewer bugs related to asynchronous logic.