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fix(lib/es2015): Fix definition of ProxyHandler - #35594
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| interface ProxyHandler<T extends object> { | ||
| getPrototypeOf? (target: T): object | null; | ||
| setPrototypeOf? (target: T, v: any): boolean; | ||
| setPrototypeOf? (target: T, v: object | null): boolean; |
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The Proxy exotic object’s [[SetPrototypeOf]] ( V ) internal method ensures that V is object | null before passing it to user code.
| get? (target: T, p: string | symbol, receiver: any): any; | ||
| set? (target: T, p: string | symbol, value: any, receiver: any): boolean; | ||
| deleteProperty? (target: T, p: string | symbol): boolean; | ||
| defineProperty? (target: T, p: string | symbol, attributes: PropertyDescriptor): boolean; |
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The Proxy exotic object doesn’t convert valid numeric indexes into numbers before passing them to user code, they remain as strings, which is how they’re actually implemented.
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numbers never really exist as object keys, it's probably the biggest "lie" in typescript 🤷♀
| set? (target: T, p: string | symbol, value: any, receiver: any): boolean; | ||
| deleteProperty? (target: T, p: string | symbol): boolean; | ||
| defineProperty? (target: T, p: string | symbol, attributes: PropertyDescriptor): boolean; | ||
| ownKeys? (target: T): ArrayLike<string | symbol>; |
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If you return anything other that a string or symbol here, this will throw a TypeError at runtime (no, numbers don’t stringified here for whatever reason; see tc39/ecma262#1804 for discussion).
On the plus side, the spec doesn’t actually require that the returned value is an Array instance, just that it has a length property and doesn’t have holes.
| defineProperty? (target: T, p: string | symbol, attributes: PropertyDescriptor): boolean; | ||
| ownKeys? (target: T): ArrayLike<string | symbol>; | ||
| apply? (target: T & ((...args: any[]) => any), thisArg: any, argArray: any[]): any; | ||
| construct? (target: T & (new (...args: any[]) => object), argArray: any[], newTarget?: any): object; |
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These will only ever get called if the wrapped object is callable or constructable, respectively.
| set? (target: T, p: PropertyKey, value: any, receiver: any): boolean; | ||
| deleteProperty? (target: T, p: PropertyKey): boolean; | ||
| defineProperty? (target: T, p: PropertyKey, attributes: PropertyDescriptor): boolean; | ||
| enumerate? (target: T): PropertyKey[]; |
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The enumerate(…) method was removed in ES2016 from both Reflect and ProxyHandlers, due to implementers deciding against it.
The type is wrong anyway, since it’s specified to return Iterator<any>.
PromiseHandlerProxyHandlerTypeScript Bot (typescript-bot)
commented
Dec 16, 2020
This PR doesn't have any linked issues. Please open an issue that references this PR. From there we can discuss and prioritise. |
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This fixes several issues I found while comparing the definition of
ProxyHandlerto what’s actually defined in the specification.Depends on:
Reflect.enumerate(…)#38967 (merged)Reflectmethods #41987 (merged)Fixes#42894