CODEWITHSUNDEEP
javascripttypesflowtype
Samuel Maisonneuve
Samuel Maisonneuve

Reputation: 1145

How do i specify a Class type argument with flow?

I've a function which receives a class as a parameter : myFunction = (Klass) => new Klass();

How do i specifiy Klass parameter with flow ?

If i use Klass:SomeClass, flow seems to be ok with that. But i was expecting this to give me an error since i thought :SomeClass would indicate "an instance of SomeClass", which is not the case in my example (i'm passing the class itself)

What is the correct notation for this example ?

Edit:

As Aleksey pointed out in the comment, we can use the Class utility : myFunction = (Klass:Class<SomeClass>) => new Klass();

Upvotes: 2

Views: 303

Answers (1)

Aleksey L.
Aleksey L.

Reputation: 37938

To represent class type (constructor function) of an instance type you can use Class utility:

class SomeClass {}

const myFunction = (c: Class<SomeClass>) => new c();

Upvotes: 4

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