IMO, one of the main concerns of the TypeScript language is to support the existing vanilla JavaScript code. This is the impression I had at first glance. Take a look at the following JavaScript function which is perfectly valid:

Note: I am not saying that I like this approach. I am just saying this is a
valid JavaScript code.

function sum(numbers) { 



    var agregatedNumber = 0; 

    for(var i = 0; i < arguments.length; i++) { 

        agregatedNumber += arguments[i];

    }



    return agregatedNumber;

}

So, we consume this function with any number of arguments:

console.log(sum(1, 5, 10, 15, 20));

However, when I try this out with TypeScript Playground, it gives compile time errors.

I am assuming that this is a bug. Let's assume that we don't have the compatibility issues. Then, is there any way to write this type of functions with open-ended arguments? Such as params feature in C#?