TypeScript Tutorial

TypeScript is a superset of JavaScript that adds optional static typing. Developed and maintained by Microsoft Corporation, TypeScript combines the familiar syntax of JavaScript with additional features and a robust type system. Improved Code Maintainability by catching errors early during development, making code easier to understand and modify.

TypeScript’s tooling provides intelligent code completion and refactoring, saving you time and effort. It helps build robust and scalable applications by preventing runtime errors often associated with untyped JavaScript. As TS code is converted to JS code it makes it easier to integrate into JavaScript projects.

In this TypeScript Tutorial, we’ll learn all the basic to advanced concepts of TypeScript such as Utility, methods, functions, etc.

For a large-scale project adopting It might result in more robust software, while still being deployable where a regular JavaScript application would run. It won’t make your software bug-free. But it can prevent a lot of type-related errors. Along with the Clever IntelliSense.

Key Features of TypeScript:

1. Static Typing:
   • TypeScript introduces static typing, ensuring that the type of a variable cannot change during program execution. This significantly reduces the chances of bugs and enhances code reliability.
   • Clear type annotations help developers understand the purpose of variables and functions, leading to improved readability.
2. Compatibility with JavaScript:
   • Your existing JavaScript code is also valid in TypeScript. This means you can gradually adopt TypeScript in your projects without rewriting everything.
   • TypeScript code is transpiled to JavaScript, making it easy to integrate into existing JavaScript applications.
3. Type Inference:
   • TypeScript infers types based on context, reducing the need for explicit type annotations. This allows developers to write cleaner code while still benefiting from static typing.
4. Advanced Language Features:
   • TypeScript supports modern ECMAScript features (ES6, ES7, etc.) and provides additional features like interfaces, classes, modules, and decorators.
   • It allows developers to write more maintainable and organized code by enforcing best practices.

Why TypeScript?

While JavaScript’s flexibility shines in quick prototyping, large-scale projects benefit from the structure and predictability TypeScript offers. Here’s when TypeScript excels:

1. Large-Scale Web Applications: TypeScript’s static typing fosters better organization and collaboration in complex projects.

2. Enterprise Applications: The robust error checking and code clarity improve reliability and maintainability in critical systems.

3. Front-End Frameworks: Many popular frameworks like Angular and React embrace TypeScript for its type safety advantages.

4. Improved Readability: Clear type annotations in TypeScript make code more readable. Developers can easily understand the purpose of variables and functions, leading to better collaboration and maintainability.

5. Deepening JavaScript Understanding:

• Even if you don’t use TypeScript extensively, learning it deepens your understanding of JavaScript.
• Appreciate language features and their impact on code quality, whether you’re writing TypeScript or plain JavaScript.

6. Robust Software Development:

• TypeScript won’t make your software bug-free, but it can prevent many type-related errors.
• For large-scale projects, adopting TypeScript results in more robust software that is still deployable where regular JavaScript applications run.

Text Editors with TypeScript Support

• Visual Studio Code with the TypeScript extension
• WebStorm
• Sublime Text with the Anaconda plugin

TypeScript Tutorial

Prerequisites: Before you start this typescript tutorial, It’s recommended you should have a basic understanding of javascript and object-oriented programming.

TypeScript Basics

• Data types
• Arrays
• String
• How to install TypeScript ?
• Hello World
• How to compile a Typescript file ?
• Variables
• Identifiers and Keywords in TypeScript
• Numbers
• Keyof Type Operator
• Union
• Object
• Class
• Tuples
• Object Extending Types
• Indexed Access Types
• Mapped Types
• Type assertions
• Method Overriding
• Accessor
• Inheritance
• Generics Interface
• Rest Parameters
• Ambients Declaration
• Duck-Typing

TypeScript Advance

• Generic Object Types
• Call Signatures
• Declaring this in a Function
• Constraints
• Construct Signatures
• Generic Parameter Defaults
• Unknown Function
• Non-null Assertion Operator (Postfix !) Type
• Object Type Optional Properties
• Conditional Types
• Object Type readonly Properties
• strictNullChecks on Type
• strictNullChecks off Type
• Exhaustiveness checking
• Writing Good Overloads
• Aliases Type
• Specifying Type Arguments
• Literal Inference Type
• Interfaces Type
• Return type void

TypeScript Utility Type

• Partial<Type>
• Record<Keys, Type>
• Awaited<Type>
• Required<Type>
• Omit<Type, Keys>
• Pick<Type, Keys>
• Extract<Type, Union>
• Capitalize <StringType>
• Lowercase <StringType>
• ConstructorParameters<Type>
• ReturnType <Type>
• Creating Types from Utility Type
• Exclude<UnionType, ExcludedMembers>
• Uncapitalize<StringType> Template Literal Type

TypeScript Functions

• toFixed() Function
• toLocaleString() Function
• toPrecision() Function

TypeScript Methods

• Number valueOf() Method
• Array toString() Method
• toExponential() Method

TypeScript Array Methods

• reduce() Method
• forEach() Method
• map() Method
• filter() Method
• splice() Method
• concat() Method
• push() Method
• sort() Method
• slice() Method
• some() Method
• indexOf() Method
• join() Method
• every() Method
• unshift() Method
• pop() Method
• reverse() Method
• shift() Method
• lastIndexOf() Method
• reduceRight() Method

TypeScript String Methods

• split() Method
• replace() Method
• concat() Method
• substring() Method
• toString() Method
• toUpperCase() Method
• toLowerCase() Method
• indexOf() Method
• toString() Function
• slice() Method with example
• search() Method
• substr() Method
• localeCompare() Method
• Length Property
• Prototype Property
• valueOf() Method
• Constructor Property
• lastIndexOf() Method
• charAt() Method
• toLocaleLowerCase() Method
• charCodeAt() Method
• toLocaleUpperCase() Method

Advantages of Using TypeScript

• TypeScript offers static typing, which allows developers to define types for variables, parameters, and return values.
• TypeScript detects errors at compile-time rather than runtime, allowing developers to catch issues early in the development process.
• TypeScript has a rich ecosystem of tools and libraries that enhance the development experience.
• It adopts the basic building blocks of your program from JavaScript. All TS code is converted into its JS equivalent for the purpose of execution.
• The support for Classes and Objects is also one of the main reasons for its increasing popularity as it makes it easier to understand and implement OOPS concepts as compared to the standard prototype-based implementation provided by native JavaScript.

TypeScript Vs JavaScript

TypeScript	JavaScript
Provides static typing	Dynamically typed
Comes with IDEs and code editors	Limited built-in tooling
Similar to JavaScript, with additional features	Standard JavaScript syntax
Backward compatible with JavaScript	Cannot run TypeScript in JavaScript files
Stronger typing can help identify errors	May require more debugging and testing

FAQs on TypeScript Tutorial

What is TypeScript?

TypeScript serves as an extension of JavaScript, integrating optional static typing into the language. With TypeScript, you can designate the data types of variables and functions, facilitating early error detection and enhancing code quality.

Is TypeScript easy to learn?

Certainly! TypeScript isn’t more difficult to grasp than JavaScript. Essentially, TypeScript acts as a refined version of JavaScript. If you’re already acquainted with JavaScript, transitioning to TypeScript shouldn’t pose significant challenges. While TypeScript introduces additional concepts like static typing, its overall similarity to JavaScript simplifies the learning curve.

Is TypeScript replacing JavaScript?

No, TypeScript isn’t poised to supplant JavaScript. Rather, it provides an optional layer of type safety atop JavaScript. This characteristic renders TypeScript a valuable asset for specific scenarios, particularly in the realm of larger and more intricate projects.

Are there any libraries or frameworks specifically for TypeScript?

There are Numerous libraries and frameworks are tailored to complement TypeScript usage. Examples include Angular, React, and Vue.js. These frameworks often furnish type definitions and supplementary features catered to TypeScript development.