type destructuring

Search Terms

type destructuring

Suggestion

Allow destructuring syntax when assigning type

Use Cases

Dynamically assign a type as the type of an other type's property.

Examples

Where AutocompleteService is a class, PlacesServiceStatus is an enum, and AutocompletePrediction is an interface.

What I'm doing currently:

const { AutocompleteService, PlacesServiceStatus } = google.maps.places;
type AutocompletePrediction = google.maps.places.AutocompletePrediction;

What I'd like to be able to do:

const { AutocompleteService, PlacesServiceStatus } = google.maps.places;
type { AutocompletePrediction } = google.maps.places;

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.

The issue proposes allowing destructuring syntax in a type assignment, with a TypeScript example showing the desired form. No implementation files, entry points, or tests are named; start by tracing how TypeScript parses and checks type aliases, then define tests that distinguish valid type destructuring from existing syntax. Done means the example type-checks without changing emitted JavaScript.