Add typed overloads to `Object.create`

Search Terms

• object.create
• object create
• typed object.create
• typed object create

Suggestion

Change the signatures of Object.create to:

interface ObjectConstructor {
	create<P extends object | null>(proto: P): null extends P ? {} : P;

	create<
		P extends object | null,
		M extends PropertyDescriptorMap = {}
	>(proto: P, properties?: M & ThisType<any>): {
		readonly [
			K in keyof M as M[K] extends { readonly writable: false }
				? K
				: never
		]: M[K] extends Readonly<TypedPropertyDescriptor<infer V>>
			? V
			: any;
	} & {
		-readonly [
			K in keyof M as M[K] extends { readonly writable: true }
				? K
				: never
		]: M[K] extends Readonly<TypedPropertyDescriptor<infer V>>
			? V
			: any;
	} & (null extends P ? {} : P);
}

Use Cases

Getting correct types in code that does:

// `foo` is `any`, because `T` of Object.assign<T, U> is `any`:
const foo = Object.assign(
	// `T` is currently typed as `any`:
	Object.create(null),

	// Only `U` is typed correctly as { bar: number; baz: string }:
	{
		bar: 123,
		baz: 'biz',
	},
);

Examples

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
  • This might need a flag similar to strictBindCallApply, or just done in a separate lib file.
• 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.

Relevant issues

• https://github.com/microsoft/TypeScript/issues/1108
• https://github.com/microsoft/TypeScript/issues/13206
• https://github.com/microsoft/TypeScript/issues/18609
• https://github.com/microsoft/TypeScript/issues/38385
• https://github.com/microsoft/TypeScript/issues/41424

Commencez par les surcharges ObjectConstructor.create proposées et les issues liées #1108, #13206, #18609, #38385 et #41424. Déterminez comment les déclarations actuelles de la bibliothèque et les problèmes de compatibilité doivent être traités ; le travail est terminé lorsque Object.create fournit les informations de type demandées sans modifier le comportement de JavaScript à l’exécution.