Is there a way to make this TypeScript narrowing less ugly (or more elegant ;-) ❓

With IsSomething type guard, I want to narrow down access to common methods and properties of any JavaScript variable which is not null and not undefined (things like .toString, .valueOf, .hasOwnProperty, .constructor etc.)

In TypeScript, the Object interface is different from the primitive object type, as the former is still assignable to any other primitive or complex type. It is also different from an empty type like type Something = {}, as the latter doesn't supports IntelliSense.

// Object interface is OK
let a: Object = 42; 
let b: Object = true;
let c: Object = "string";
let d: Object = Symbol(42);
let e: Object = new class SomeClass { someProp = 42 };

// Empty type is OK but no IntelliSense 
let a1: {} = 42; 

// Error: Type 'number' is not assignable to type 'object'
let a2: object = 42; 

Playground link.

One subtle issue still remains. As @CertainPerformance pointed out, the above won't work for an edge case like Object.create(null), where an object is created which doesn't have any properties or methods, but isn't null either.

If that's a requirement, the following should do the job:

// can be extended to check for toString, valueOf, etc
export function IsSomething(value: unknown) : value is Object {
  return (<Object>value)?.constructor !== undefined;
}

Narrowing([1, 2, 3]);

function Narrowing(o: unknown) { // OK
  if (IsSomething(o)) {
    console.log(o.toString(), o.constructor);
  }
}