Room 51

Room 51 is the personal site of John Larsen, a web developer, ex-maths teacher, certified Japanophile and author of React Hooks in Action and Get Programming with JavaScript.

Latest Tutorial: Managing component state with the useState hook.

Interactions between React and a component when calling useState

React Hooks in Action

React Hooks in Action

Published Summer/Fall 2020

React Hooks in Action is available to buy from Manning.

Use code larsenpc for 40% off!

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Build stylish, slick, and speedy-to-load user interfaces in React without writing custom classes. React Hooks are a new category of functions that help you to manage state, lifecycle and side effects within functional components. React Hooks in Action teaches you to use pre-built hooks like useState, useReducer and useEffect, and to build your own hooks. Your code will be more reusable, require less boilerplate, and you’ll instantly be a more effective React developer.

Get Programming with JavaScript

Get Programming with JavaScript

Published August 2016

Get Programming with JavaScript is available to buy from Manning, Amazon or any book store of your choice!

Buy now at

Buy now at

Get Programming with JavaScript is a practical introduction to programming. Through hands-on code samples coupled with carefully paced explanations, supporting video tutorials and a wide variety of examples, it will help you build knowledge and skills and set you on your way to coding expertise.

Further Learning

A selection of resources related to JavaScript and React programming.

These are affiliate links - I get a payment for each sale on the Wes Bos and Manning sites if you follow these links.

Courses by Wes Bos

Wes Bos has created some fantastic video courses to take your JavaScript skills to the next level:

JavaScript30 (It's Free!)

Beginner JavaScript

ES6 for Everyone

React for Beginners

Fullstack Advanced React and GraphQL

Learn Redux (It's Free!)

Learn Node

There are lots of good JavaScript books at Manning to guide you on further programming adventures.

Books from Manning

Manning publish a number of intermediate and more advanced JavaScript books, including:

Secrets of the JavaScript Ninja

Functional Programming in JavaScript

JavaScript Application Design

Get Programming with JavaScript Next

Isomorphic Web Applications

Deep Learning with JavaScript

The Joy of JavaScript

React in Action

Redux in Action

Node.js in Action

Express in Action

Getting MEAN with Mongo, Express, Angular, and Node

Manning often issue promotional discount codes, so it's worth watching their site for deals, signing up to newsletters and following their accounts on Twitter.

These are affiliate links - I get a payment for each sale on the Wes Bos and Manning sites if you follow these links.