Type JS's `arguments` object based on function parameters

Search Terms

type "arguments" object parameters

Suggestion

Within a function x, the type of the arguments object should be Parameters<typeof x> & IArguments, with undefined removed from the type of any entries in Parameters<typeof x> if that parameter has a default value.

Use Cases

class A {
   fn(it: number) { return true; }
}

class B extends A {
  fn(it: number) {
    // this shouldn't error, because arguments must be at least length 1.
    // instead we get ERROR: Expected 1 arguments, but got 0 or more.
    return super.fn(...arguments); 
  }
}

Checklist

My suggestion meets these guidelines:

• [?] This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

Non viene indicato alcun file sorgente, test o punto di ingresso del compilatore. Inizia riproducendo l'esempio di classe A/B e verifica come vengono attualmente controllati l'oggetto arguments, Parameters<typeof x>, i parametri predefiniti e super.fn(...arguments); il lavoro è completato quando l'esempio non segnala più l'errore sul numero di argomenti indicato, preservando al contempo il comportamento a runtime.