IntersectionType clause for more than 4 classes is not available in the npm version

[marekbrainhub]

Is there an existing issue for this?

• I have searched the existing issues

Current behavior

Using IntersectionType on more than 4 classes produces a TypeScript error.

Minimum reproduction code

n/a

Steps to reproduce

class ClassA {}
class ClassB {}
class ClassC {}
class ClassD {}
class ClassE {}
IntersectionType(ClassA, ClassB, ClassC, ClassD, ClassE)

<snip>:10:50 - error TS2554: Expected 2-4 arguments, but got 5.

8  IntersectionType(ClassA, ClassB, ClassC, ClassD, ClassE)
                                                    ~~~~~~

Expected behavior

TypeScript does not complain about more than four arguments.

Package version

1.1.0

Node.js version

18.7.0

In which operating systems have you tested?

• macOS
• Windows
• Linux

Other

I suspect this is because the declaration file in the compiled library does not have the wildcard clause. I'm not sure if that is intended or if there is a workaround.

[micalevisk]

that's expected

mapped-types/lib/intersection-type.helper.ts

Lines 9 to 25 in 8c83b92

	export function IntersectionType<A, B>(
	target: Type<A>,
	source: Type<B>,
	): MappedType<A & B>;
	export function IntersectionType<A, B, C>(
	target: Type<A>,
	sourceB: Type<B>,
	sourceC: Type<C>,
	): MappedType<A & B & C>;
	export function IntersectionType<A, B, C, D>(
	target: Type<A>,
	sourceB: Type<B>,
	sourceC: Type<C>,
	sourceD: Type<D>,
	): MappedType<A & B & C & D>;

not sure if we should add more one level

[jmcdo29]

We could add another level, or you could just nest the IntersectionType classes. IntersectionType(ClassA, ClassB, IntersectionType(ClassC, ClassD), ClassE) ad infinitum as necessary

[micalevisk]

indeed. That sounds better to me. Otherwise someone may request another level again and again

[kamilmysliwiec]

#860 (comment)