TypeScript - Mapped Types

In this episode I talk about the Mapped Types in TypeScript.
00:05 What are Mapped Types?
01:17 Readonly Mapped Type example
02:26 Mapped Type syntax explained
03:15 Generic Readonly Mapped Type example
04:17 Generic Partial Mapped Type example
05:03 Combining Mapped Types
05:26 Generic Nullable Mapped Type example
06:42 Proxy Mapped Type example
08:04 Included Mapped Types in TypeScript

You can see all the code here:

Index Types Operators:

Learn TypeScript:

[ProgramArtist]

Let me know what would you like me to talk about, it can be anything as long as it is programming related

[undeadspez]

Wow! Finally found an advanced tutorial for TS. So tired of beginner ones.

[alisawari]

the best typescript video ever! thank you very much for this great video!

[nderezic]

As far as I understand it, this is a type transform operator. Each of the "Mapped Types" would in JavaScript terminology be a function, which accepts type as argument, which is then used to create a new type, which is then returned. For example an JavaScript equivalent would look like this:
function ReadOnly(InputType) {
let NewType = {};
foreach(key in inputType) {
NewType[key] = readonly InputType[key];
}
return(NewType);
}

IMGO TypeScript goes against the usual logic of the JavaScript language ... or even TypeScript - it's a language of it's own right!