class MyClass {
public static createKey(id): string {
...
}

constructor(id, value) {
...
}

public setId(newId) {
...
}
}

console.log(ReflectParams(MyClass.createKey)); // prints ['id']
console.log(ReflectParams(MyClass.prototype.constructor)); // prints ['id', 'value']

const myClassInstance = new MyClass('ID1', 100);
console.log(ReflectParams(myClassInstance.setId)); // prints ['newId']

console.log(ReflectParams(a => 'b')); // prints ['that']
console.log(ReflectParams((a, b, c) => 'abc')); // prints ['a', 'b', 'c']
console.log(ReflectParams(() => '')); // prints []

function myFunction(name, nationality) {
...
}

console.log(ReflectParams(myFunction)); // prints ['name', 'nationality']

class MyClass {
public static createKey(id: string): string {
...
}

constructor(id: string, value: number) {
...
}

public setId(newId: string) {
...
}
}

console.log(ReflectParams(MyClass.createKey)); // prints ['id']
console.log(ReflectParams(MyClass.prototype.constructor)); // prints ['id', 'value']

const myClassInstance = new MyClass('ID1', 100);
console.log(ReflectParams(myClassInstance.setId)); // prints ['newId']

console.log(ReflectParams(a => 'b')); // prints ['that']
console.log(ReflectParams((a, b, c) => 'abc')); // prints ['a', 'b', 'c']
console.log(ReflectParams(() => '')); // prints []

function myFunction(name: string, nationality: string) {
...
}

console.log(ReflectParams(myFunction)); // prints ['name', 'nationality']