what does this symbol mean in the typescript '< >'?

Question

I am a beginner in Typescript and JavaScript trying to understand a code. I encounter "< >" at several places in the code, as described in an example below.

(value: any, manager: ManagerBase<any>|undefined)

Why we use "< >" in typescript.

Thanks

Answer 1

ManagerBase is a generic type. It uses a parameter for a type in its definition (not present in the code you posted).

Let's say we have the type Sample<T> defined like this:

type Sample<T> = T[];

This makes Sample<T> an alias of the type "array of values of type T". The type Sample<number> is the same as number[], Sample<string> is the same as string[] and so on. Sample<any> is the same as any[].

In the code you posted, the type ManagerBase<any> uses any as the value of T.

Read about "generics" in the TypeScript handbook.

Answer 2

This symbol is used to specify the type when using generics. See the official TypeScript-Documentation for further information: https://www.typescriptlang.org/docs/handbook/generics.html