Over the past few months I became a TypeScript contributor and implemented a new feature, type predicate inference, that should be one of the headliners for TypeScript 5.5. This post tells the story of how that happened: why I wanted to contribute to TypeScript, the journey to implementing the feature and getting the PR merged, and what I've learned along the way. This is not a short read, but it will give you a good sense of what it's like to become a TypeScript contributor and develop a new...
