Why do we have to copy the members of interface to class definitions?

[e-cloud]

see

tsd-jsdoc/src/Emitter.ts

Line 335 in 07c6298

private _resolveInterfaceMembers(docs: TDoclet[]) {

a reasonable version

// jsdoc marked as mixin
interface A {
	a(): void;
}

// jsdoc marked as interface
interface B {
	b(): void;
}

class C implements A, B {
}

current output

// jsdoc marked as mixin
interface A {
	a(): void;
}

// jsdoc marked as interface
interface B {
	b(): void;
}

class C implements A, B {
	static a(): void;
	b(): void;
}

The reason of static occurrence is because in jsdoc mixins do not apply scope: instance.

I can not figure out why should we copy those members to class. IMO, it's unnecessary.

[englercj]

Because the first thing you listed is invalid Typescript.

Class 'C' incorrectly implements interface 'A'.
  Property 'a' is missing in type 'C'.
Class 'C' incorrectly implements interface 'B'.
  Property 'b' is missing in type 'C'.

A class that implements an interface must define the items it implements.

[e-cloud]

Emmmmm, @englercj you are right. We may achieve the same goal via simpler solution. See microsoft/TypeScript#340 (comment)

[englercj]

Seems reasonable, happy to merge a PR that uses namespace merging instead of copying members.

[englercj]

v2 was just released and after the rewrite I used this namespace merging technique for classes that implement interfaces.