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.

Lies zunächst das vorgeschlagene Verhalten von int32/BitwiseInt32 und die verknüpfte ECMAScript-Spezifikation für Bitwise-Operatoren. Verfolge, wie TypeScript die Rückgabetypen von Bitwise-Operatoren darstellt, und prüfe das coerce-Beispiel. Erledigt ist die Aufgabe, wenn Bitwise-Operatoren den vorgeschlagenen Subtyp offenlegen und weiterhin number zugewiesen werden können und Design und Benennung geklärt sind.