Migrating an Ejected Create React App to TypeScript
I love Create React App, and I also love TypeScript. That means I really love react-scripts-ts, which is a great way to spin up a new SPA for experimental purposes.
TypeScript
Mocking TypeScript Modules with Sinon
Lately, my team has been looking for better ways to create and maintain mocks in our TypeScript project. In particular, we wanted an easy way to mock out modules that we built using Sinon.JS.
Styling Custom Components in React Native Using TypeScript
I recently ran into an issue with providing style properties to custom React Native components written in TypeScript. When defining the type of the style property, we were using the ViewStyle and TextStyle types provided by React Native. interface Props { textStyle?: TextStyle; viewStyle?: ViewStyle; } class BlogPost extends React.PureComponent<Props> { render() { return ( <View […]
Type-Safe Object Merging (TypeScript 2.8 Edition)
There are times when you want to merge two generic types in TypeScript, and type inference just isn’t doing it for you. Object.assign’s typing isn’t as precise as it could be, and spreading generics still doesn’t work. I’ve found a way to implement typing when merging objects using some of the new features in TypeScript […]
Statically Typed Data Validation with JSON Schema and TypeScript
One super common problem on TypeScript projects is figuring out how to validate data from external sources and tie that validated data to TypeScript types. In these situations, you generally have a few options: Define types and validations separately, and type them together with Type Guards. Use an internal DSL such as io-ts to build […]
Simple Error Either in TypeScript
When writing a function, I often want to return either the successful value or an error. Given that my current project is in TypeScript, we came up with a nice little Either pattern for returning successes or errors.
Experiments in Purely Functional TypeScript
Recently, I’ve been experimenting with using functional programming in my side projects. Today, I want to share some of what I’ve learned, focusing on utilities I’ve created to facilitate purely functional TypeScript programming. Different Ways to Define Similar Functions Here are three versions of *roughly* the same function: const doubleAll = (array: number[]) => { […]
Flavoring: Flexible Nominal Typing for TypeScript
Recently, we’ve been making heavy use of TypeScript at Atomic Object. We love the great tooling and instant feedback we get with the language’s powerful type system. TypeScript’s structural type system gives us a lot of powerful tools for making invalid states unrepresentable, thereby pointing out bugs at compile time instead of runtime. However, one […]
Creating Your Own TSLint Rules
If you’re using TypeScript, you probably lint your code with TSLint. It has tons of useful presets that can be easily configured to your liking. Perhaps, though, you want to dig a bit deeper and create rules of your own. In this post, I’ll walk you through the steps I took to create my first […]
A Simple, Functional Module Pattern for TypeScript
We’ve been using TypeScript with our React apps quite a bit recently. One common need that we have when programming in a functional style is a good pattern for creating small abstractions that can be used widely in an application.