Add support for Inferring types

[denchen]

First off, great library. My request is that mergician would infer the type of the object passed in, or at least allow a generic

From the types definition, I see this:

export function mergician(...objects: object[]): object;

So the result is always of type object. But it would be nice if we could do this:

const obj1: MyType = { ... };
const obj2: Partial<MyType> = { ... };
const newObject1 = mergician(obj1, obj2); // newObject1 is now of type MyType

const newObject2 = mergician<MyType>({}, obj1); // newObject2 is cast as MyType

[BrendonSled]

Create a mergician.d.ts in your src folder with this for the typings:

type MergicianObjectIntersection<T extends unknown[]> = T extends [infer First, ...infer Rest]
    ? First & MergicianObjectIntersection<Rest>
    : unknown;

declare module 'mergician' {
    function mergician<T extends object[]>(...objects: T): MergicianObjectIntersection<T>;
}