Infer type when object coerced to string if toString explicitly defined

Search Terms

coercion toString computed properties

Suggestion

Infer type when object coerced to string if toString explicitly defined

Examples

Would be nice if the following would be allowed

const action = {
  type: 'foo',
  toString() { return this.type }
} as const;

const reducerHandler = {
  [action]: () => { } // Currently errors: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
}

Playground

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.

Run the linked TypeScript Playground example and inspect the current computed-property-name error. Determine how explicit toString definitions should affect type checking, then verify that the example is accepted without changing emitted JavaScript and that coverage is added for the behavior.