Course outline for TypeScript

From JavaScript to TypeScript

• Static checking and JavaScript runtime behavior
• Installing the compiler and inspecting emitted JavaScript
• Project structure, tsconfig, and strict mode
• Reading compiler diagnostics

Types and Inference

• Primitive, array, tuple, and object types
• Type inference and annotations
• Optional properties and readonly data
• Choosing unknown rather than unconstrained any

Functions and Object Contracts

• Parameter and return types
• Interfaces and type aliases
• Function types and overloads
• Structural compatibility and excess-property checks

Unions and Narrowing

• Literal types and discriminated unions
• Null and undefined handling
• Control-flow narrowing and type guards
• Exhaustive handling with never

Generics and Reusable Types

• Generic functions and constraints
• keyof, indexed access, and mapped types
• Common utility types
• Keeping reusable types readable

Modules and Application Boundaries

• Imports, exports, and declaration files
• Module resolution and compiler targets
• Typing third-party packages
• Separating static types from runtime input validation

Asynchronous Code and Testing

• Typed promises and asynchronous results
• Modeling success and failure states
• Unit tests and type-checking in CI
• Debugging with source maps

JavaScript Migration

• Introducing checks one module at a time
• Working with JavaScript files and JSDoc
• Replacing unsafe assertions and suppressions
• Reviewing dependency and build compatibility

Practical Exercise

• Implement a typed client for a supplied local API
• Reject malformed input and handle every response variant
• Refactor one JavaScript module without changing its behavior
• Run the compiler and tests and document the remaining runtime checks