Carl Topham

React.js & JavaScript developer


Recent articles

Putting the `S` in SOLID JavaScript

February 16, 2021

S - Single-Responsibility Principle (SRP) is the first design principal covered by SOLID principals.

SOLID is an Object oriented design principal. It stands for:

  • S - Single-responsiblity Principle
  • O - Open-closed Principle
  • L - Liskov Substitution Principle
  • I - Interface Segregation Principle
  • D - Dependency Inversion Principle

The principals were originally created and promoted by Robert Martin (aka Uncle Bob).

SRP simply states that Classes and functions should only have a single responsibility. This sounds...

Getting started with Blender

February 13, 2021

I recently picked up 3d modelling after quite a few years away. I have not used Blender before so learning the basics involved many seaches and skimming videos to fine what I needed. This post is a quick guide to getting started with blender that I have created from my notes.

Hopefully it will enable you to get started more quickly than I did!


Firstly if you're on a (mac) laptop without a numpad then you will want to enable numpad emulation. This will allow you to use the normal numbers to navigate...

React and Material UI (MUI)

January 8, 2021

When I first used Material UI, I struggled with a few concepts. I've written this quick overview to help get my head around it, and hopefully guide others to a quicker start.

I'm going to make a new project and then create some (horrible) styles!

Create the project and add MUI

Create a project and install the Material UI package

npx create-react-app material-ui-playground 
cd material-ui-playground 
yarn add @material-ui/core 

Clean up the initial templates

Remove some unused contents (import of the styles)...

Formatting percentage values with JavaScript Intl

January 5, 2021

Javascript contains an Internationalization API that you can use to format numbers to a user's locale. Setting the style to percent is all that is needed.

Intl.NumberFormat("en-GB", { style: "percent"}).format(1.2345); // => "123%" 

Note: A value of 1 will return 100% because 1x anything is 100%!

1 * 100 = 100; // 100%  1.5 * 100 = 150; // 150%  

To specify the decimal places use minimumFractionDigits and maximumFractionDigits to give you more visual control.

Intl.NumberFormat("en-GB", { style: "percent",...

Formatting currency with JavaScript Intl

December 17, 2020

Javascript's Internationalization API allows you to format currency. It takes the locale and options to configure the currency we're using. The options require the style to be set to currency and a currency option to specify the unit type, as this is returned as part of the result.

Intl.NumberFormat("LOCALE", { style: "currency", currency: "CURRENCY UNIT"}).format(VALUE); // => "€1.23" 

The following example formats a EUR (Euro) currency of the value 1.2345 into a en-GB (English - Great Britain) format.


Recent projects

Migrate from Gatsby to Next.js

Rebuild my portfolio site ( in Next.js, migrating from Gatsby

Running kit bag

Interactive kit bag checklist app to ensure that I always have the right running kit for training, races and all weather!

SmartSave & LiveLend WebApps

React.js Redux WebApps using REST APIs with Auth.

Advanced Strava Stats

Sync your Strava data and analyse it in extra ways than the official app. React, Redux, Saga, Axios & D3.

SmartSave Public Website

Wagtail/Django/Python backend with WebPack, React & Bootstrap frontend