int32 type returned by bitwise operators

Search Terms

bitwise operators, integer type, int32

Suggestion

Add an int32 subtype for number returned by TypeScript from bitwise operators.

function coerce(n: number): int32 {
  return n | 0;
}

JavaScript bitwise operators coerce arguments to int32 and the return type of those operators will always be an int32.

This would not be a breaking change since int32 would be a subtype of number. Only bitwise operations would change to return int32s.

EDIT: I now recommend calling the type BitwiseInt32 so that user’s won’t see the type as a generic integer type.

Use Cases

Helps applications which are trying to take advantage of JavaScript implementations int32 optimizations. An application could ask for an int32 parameter to force coercion with n | 0.

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.

Commencez par lire le comportement proposé de int32/BitwiseInt32 ainsi que la spécification ECMAScript liée concernant les opérateurs bit à bit. Suivez la manière dont TypeScript représente les types de retour des opérateurs bit à bit et vérifiez l’exemple coerce. Le travail est considéré comme terminé lorsque les opérateurs bit à bit exposent le sous-type proposé tout en restant assignables à number, et que la conception et le nommage sont définis.