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Here's something that makes me feel old: in just six months, Gmail will celebrate its 20th anniversary. If you weren't actively developing web sites at the time, it's hard to capture just how revolutionary it was. This was a time when JavaScript was held in almost universally low regard. The idea that you could build a sophisticated web app using it was mind-boggling. But it clearly worked and it

Readers of Effective TypeScript and followers of this blog will know that testing types is a long-standing interest of mine: typings-checker (2017) implemented $ExpectType and $ExpectError directives and helped to influence dtslint, which is used to test types on DefinitelyTyped. I gave a talk at TSConf 2019 entitled Testing Types: An Introduction to dtslint. I included Item 52: Be Aware of the Pi

Software engineering is a battle against complexity. Without any planning or care, it's easy to build programs where everything interacts with everything else (the "big ball of yarn" model). With a ball of yarn, if you double the number of components, you quadruple the number of interactions: One of the best ways to fight against this ramp-up of complexity is to simply reduce N, i.e. to write fewe

TypeScript is a typed superset of JavaScript with the potential to solve many of the headaches for which JavaScript is famous. But TypeScript has a learning curve of its own, and understanding how to use it effectively can take time. Effective TypeScript (2nd Edition) guides you through 83 specific ways to improve your use of TypeScript, following the format popularized by Effective C++ and Effect

The New TypeScript Handbook has some real gems in it. Here's what it has to say about generics: Writing generic functions is fun, and it can be easy to get carried away with type parameters. Having too many type parameters or using constraints where they aren't needed can make inference less successful, frustrating callers of your function. It goes on to offer a few specific pieces of advice about