Tutorials/TypeScript

TypeScript tutorial

JavaScript with static types for dependable code.

23 lessonsExamples and guided walkthroughs

Start learning View examples

Course contents

Programming fundamentals

TypeScript Types

Describe values before runtime.

TypeScript Union Types and Narrowing

Accept more than one type and narrow it safely with typeof.

TypeScript literal types and as const

Build a union of allowed strings from an object or array and make switch statements exhaustive.

TypeScript unknown and user-defined type guards

Validate parsed JSON at run time and let the compiler trust the result only after the check.

TypeScript tuples, readonly, and optional chaining

Return fixed-shape pairs, protect arrays from change, and read nested optional values safely.

Object-oriented programming

TypeScript Interfaces

Describe the shape of an object, including optional properties.

TypeScript abstract classes and access modifiers

Use private, protected, readonly, and abstract to describe what subclasses and outside code may do.

Data structures and algorithms

TypeScript Generics

Write one function that keeps the type of whatever it receives.

TypeScript generic stack and queue

Write containers that work for any element type and keep it checked.

TypeScript generic binary search tree

Order any type with a comparator function and collect the values in sorted order.

TypeScript typed comparators and multi-key sorting

Build comparators from a key with keyof, and combine them to sort by several fields.

Analysis of algorithms

TypeScript: a typed memoize wrapper

Cache the results of a pure function with a generic higher-order function and count how often the body runs.

Database systems

TypeScript: type-safe select, where, and orderBy

Write small query helpers whose column names are checked by the compiler with keyof.

Operating systems

TypeScript: a process lifecycle as a typed state machine

Allow only legal transitions between process states and reject the rest.

Computer networks

TypeScript: parsing a raw HTTP request into a typed object

Split the request line, headers, and body of an HTTP/1.1 message and read a query parameter.

Software engineering

TypeScript: explicit errors with a Result type

Return success or failure as a value, and let the compiler force the caller to handle both.

Information security

TypeScript: branded types for validated and escaped data

Use the type system so that unvalidated text cannot be passed where a validated value is required.

Parallel and distributed computing

TypeScript: running async tasks with a concurrency limit

Start at most N tasks at once, collect results in input order, and measure the peak concurrency.

Artificial intelligence

TypeScript: a generic breadth-first search solves the water-jug puzzle

Write the search once for any state type and apply it to two jugs.

Knowledge representation and reasoning

TypeScript: propositional formulas as a discriminated union

Represent formulas as trees, evaluate them for any assignment, and test for tautologies.

Machine learning

TypeScript: precision, recall, and F1 from a confusion matrix

Count true and false positives and negatives with a typed interface, then compute the metrics.

Neural networks and deep learning

TypeScript: composing neural-network layers behind an interface

Build a small network from Dense and Sigmoid layers that share one Layer interface.

Computer vision

TypeScript: a grayscale image class with threshold and flip

Wrap a flat pixel buffer in a class that checks bounds and returns new images from its operations.