144: Gary Bernhardt - TypeScript and Testing

Topics include: Why Gary decided to write Execute Program as a full-stack TypeScript application instead of using a Ruby or Python backend like he may have traditionally Do you actually have to write less tests if you have a good type system? What does a good type system give you that tests can't give you? Using io-ts to type check incoming data How to think about structuring your code to best take advantage of the benefits your type system gives you and minimize the need to write tests Pushing conditional logic to the core of your system to reduce the number of tests you need to write at the edges The correlation between type errors and behavioral bugs, and how a type system can help you catch mistakes you don't think to test for Do type errors signal that you're missing a test? Structural vs. nominal type systems, and the benefits of structural type systems like used by TypeScript and Go Best practices for type-checking within a function in a structural type system like TypeScript The power of supporting literal types like true or "active" in addition to traditional types Links: Destroy All Software Execute Program TypeScript "Are tests necessary in TypeScript?" io-ts TypeScript course on Execute Program Gary's tweet about unions with literal types Supporting the show: I decided to stop taking sponsors for the show because I think advertisements are annoying and no one wants to listen to them. If you do want to support the show, the best way to do it is to purchase one of my products: Tailwind UI, a collection of professionally designed, fully responsive HTML components built with Tailwind CSS. Refactoring UI, a book and video series I put together with Steve Schoger on designing beautiful user interfaces, without relying on a designer. Advanced Vue Component Design, a course on designing simpler, more flexible Vue components that are both more powerful and easier to maintain. Test-Driven Laravel, a massive video course on designing robust Laravel applications with TDD. Learn how to build a real-world application from scratch without writing a single line of untested code. Refactoring to Collections, a book and video course that teaches you how to apply functional programming principles to break down ugly, complex code into simple transformations — free of loops, complex conditionals, and temporary variables.