Includes Typescript Type Challenges 898 Easy

Summary

The ability to mark a field as readonly is one of the fundamental tools in the TrimLeft` is the first in a multi-day series on some string manipulation methods. Confusingly, we almost have to solve tomorrow's ... Replace` is starting to feel we're implementing regular expressions in Awaited is a nice early look at how recursive types look in We tend to take it for granted, but the first versions of Readonly 2` should be called `Readonly By Keys`. It provides the same functionality as Readonly (a previous Let's solve First of Array 00:00 Intro 00:14 First of Array