TypeScript 5.5

devblogs.microsoft.com

7 pointsstyfle3 comments

Many of us had given up hope that what ended being the "Inferred Predicate Types" feature of this release could ever be possible... and in the end, it was just like 10 lines of code!!

If you like technical deep dives on new TypeScript features, we did just such a deep dive[1] on this feature's PR with the author himself, Dan Vanderkam. He goes through how he got the idea and motivation for what ended up being a really creative fix.

[1] https://youtu.be/LTuzl2r2HjA

regarding the "Isolated Declarations" items from TypeScript 5.5: next week we're doing a PR code review/interview with Titian Cernicova-Dragomir, one of the main people pushing that work. It'll be very similar in scope/style to the one above with Dan Vanderkam. If you have questions to ask Titian about it, let us know and we'll ask him next week!

btw: Dan Vanderkam's book "Effective TypeScript: 83 Specific Ways to Improve Your TypeScript" (which _just_ released) includes TypeScript 5.5. Even after writing TypeScript for many years I found a lot of really practically applicable stuff in it. If you like books, this is a really good one.

[1] https://www.amazon.com/Effective-TypeScript-Specific-Ways-Im...

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