Start Me Up: ts-loader meet .tsbuildinfo

With TypeScript 3.4, a new behaviour landed and a magical new file type appeared; .tsbuildinfo

TypeScript 3.4 introduces a new flag called --incremental which tells TypeScript to save information about the project graph from the last compilation. The next time TypeScript is invoked with --incremental, it will use that information to detect the least costly way to type-check and emit changes to your project.

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These .tsbuildinfo files can be safely deleted and don’t have any impact on our code at runtime - they’re purely used to make compilations faster.

This was all very exciting, but until the release of TypeScript 3.6 there were no APIs available to allow third party tools like ts-loader to hook into them. The wait is over! Because with TypeScript 3.6 the APIs landed: https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-6.html#apis-to-support---build-and---incremental

This was the handiwork of the very excellent @sheetalkamat of the TypeScript team - you can see her PR here: https://github.com/microsoft/TypeScript/pull/31432

What's more, Sheetal took the PR for a test drive using ts-loader, and her hard work has just shipped with v6.2.0:

• https://github.com/TypeStrong/ts-loader/pull/1012
• https://github.com/TypeStrong/ts-loader/pull/1017

If you're a ts-loader user, and you're using TypeScript 3.6+ then you can get the benefit of this now. That is, if you make use of the experimentalWatchApi: true option. With this set:

1. ts-loader will both emit and consume the .tsbuildinfo artefact.

2. This applies both when a project has tsconfig.json options composite or incremental set to true.

3. The net result of people using this should be faster cold starts in build time where a previous compilation has taken place.

ts-loader v7.0.0

We would love for you to take this new functionality for a spin. Partly because we think it will make your life better. And partly because we're planning to make using the watch API the default behaviour of ts-loader when we come to ship v7.0.0.

If you can take this for a spin before we make that change we'd be so grateful. Thanks so much to Sheetal for persevering away on this feature. It's amazing work and so very appreciated.

Coming Soon: Definitely Typed

A long time ago (well, 2012) in a galaxy far, far away (okay; Plovdiv, Bulgaria)....

Definitely Typed began!

This is a project that set out to provide type definitions for every JavaScript library that lacked them. An ambitious goal. Have you ever wondered what the story that lay behind it was?

Perhaps you know that the project was started by a shadowy figure named "Boris Yankov". And maybe you know that the TypeScript team is now part of the Definitely Typed team. There's a lot more to tell.

This autumn, I'd like to tell you the story of how Definitely Typed came to be what it is. From an individual commit in a repo that Boris created in 2012 to the number 10 project by contributions on GitHub in 2018. I'm part of that story. Basarat Ali Syed is part of that story. Masahi Wakame too. Blake Embrey. Steve Fenton. Igor Oleinikov. It's an amazing and unexpected tale. One that turns upon the actions of individuals. They changed your life and I'd love you to learn how.

So, coming soon to a blog post near you, is the story of Definitely Typed. It's very exciting! Stay tuned...