Introduction to TypeScript

• TypeScript is a syntactic superset of JavaScript.
• Adds static typing to prevent common coding errors.
• Catches errors during development that JavaScript wouldn't.
• Acts like a buddy who double-checks your code.

Installing TypeScript

1. Install TypeScript:
   • Command: npm install typescript -D
2. Initialize a configuration file:
   • Command: npx tsc --init

Understanding the TS Configuration File

• The tsconfig.json file contains several important fields:
  • compilerOptions: Customizable settings for TypeScript.
    • target: Specifies the JavaScript version (e.g., ES2020, ESNext).
    • module: Default is CommonJS, can switch to ESNext or ES6.
    • esModuleInterop: Smoothes compatibility between module systems.
    • forceConsistentCasingInFileNames: Ensures case-sensitive imports.
    • strict: Enables strict type checking.
    • skipLibCheck: Skips type checking for library files to speed up compilation.

Using TypeScript for User Input Validation

• Example: Create a user registration form.
  • Ensure input values are of the correct type (e.g., name should be a string).
• TypeScript catches errors like passing a number when a string is expected.

Working with Variables

• Variable Types:
  • Strings, numbers, booleans, arrays.
  • Example: A discount variable should only accept numbers to prevent revenue loss.
• Union Types: Allow a variable to accept multiple types (e.g., string | number).
  • Useful for situations like tracking top-selling products which could be strings or numbers.

Functions in TypeScript

• Ensure function inputs and outputs have the correct type.
  • Example: Loan calculation function that only accepts numbers.
  • Use type annotations to enforce return types, preventing bugs.

Working with Objects and Interfaces

• Use Interfaces to define the structure of objects (e.g., employee data) to ensure consistency.
  • Make properties optional using a question mark (e.g., position?).

Type Aliases and Literal Types

• Type Aliases: Give a new name to a type, enhancing readability.
  • Example: Alias for username.
• Literal Types: Restrict a type to specific string values (e.g., roles like "admin", "user").

Enums in TypeScript

• Define named constant values for better readability and error prevention.
  • Example: Subscription tiers or HTTP status codes.

Generics in TypeScript

• Generics: Create reusable components that work for multiple data types.
  • Example: Generic function identity ensuring input and output types match.
  • Acts as a placeholder (e.g., T) for type safety.

Conclusion

• This overview covers the basics of TypeScript.
• More advanced features will be discussed in future videos.
• PDF version of the content available for reference.
• Encourage viewers to subscribe for more learning resources.