Document Utility Types (Predefined types)

[csantos42]

Opening this issue in response to microsoft/TypeScript#24558.

I am currently working on a PR to add a new page to the Handbook titled Utility Types (open to suggestions on the title & location of this documentation).

Note that Utility Types is a natural name for these utilities as it's the name adopted by Flow, and more importantly, it's the terminology originally used in the release notes for TS 2.1 to describe several of these utilities.

This PR will document the utility types below:

• Partial<T>
• Readonly<T>
• Record<K, T>
• Pick<T, K>
• Exclude<T, U>
• Extract<T, U>
• NonNullable<T>
• ReturnType<T>
• InstanceType<T>
• Required<T>
• ThisType<T> (would resolve Document ThisType<T> #649)

Feedback appreciated!

[hronro]

Hi @chrissantos1995 @RyanCavanaugh
I notice although the PR is merged, I can't find the utility types docs in typescript homepage in anywhere. But actually that docs can be opened by manually typed url "https://www.typescriptlang.org/docs/handbook/utility-types.html".
I guess something is missing in the static site builder config?

[karlhorky]

@foisonocean the side navigation has been updated as of microsoft/TypeScript-Website#1.