microsoft / microsoft/TypeScript

Introduce 'extends type' and 'extends modifier' or phantom types to simplify the language and speed it up.

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Beschreibung

Basically when using [k in keyof] and mutating structures in ways that can be found at these repositories it becomes apparent that to simplify the learning cure it would be better if the type modifiers such as optional/required/undefined/readonly|null can be accessed and interrogated separately from the type and modifiers mashed together..
So one can focus on writing a routine that would iterate the type to be integorate for the architectural structure/shape if to call it that, which allow one to write super fast simple methods to recursively no the difference between Record<string,any>, Array, never, unknown. instead of having to do the following: T extends Record<string,any> | undefined | readonly | null ? then recuse, else step over.

The following type integogation operators.

  1. extends ? mix of the type and modifiers
  2. extends type ? just the base type without any modifiers (can only be single type else undefined)
    so string | number = undefined, string = string, number = number, array = array, record = record, class = class, constructor = constructor, one needs to be able to differential record, which is interface from Date so require have a phantom type if the interface was generate from a class or something the features a constructor. Otherwise one will iterate into custom types like Date, which is a problem.
  3. extends modifiers ? Which just allows evaluation of modifiers. hopefully not a list in the backend implementation of the compiler code, hopefully just true and false flags for speed

Phantom types

Maybe just implement the concept of phantom symbols, that don't actually exists, were by optional/required, nullable, readonly, type can be access like :
T[PT.Required] extends true ? ..
T[PT.Nullable] extends true ? ...
T[PT.Readonly] extends true ? ...
T[PT.Type] extends true ? ...
T[PT.Cusom] extends true ? ... // For passing other information that doesn't exist to validate typings.
allow one to create the own phantom types, which information we will pass onto for downstream validation in some complex situations like Mongoose Update Statement validation which has 3 parts.

Work around Mongoose Update Statment

Work around Mongoose Types

https://github.com/Microsoft/TypeScript/issues/28699

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.

Beitragsleitfaden

Beitragsleitfaden öffnen

Erste Schritte

  1. Lies das ganze Issue und danach den Beitragsleitfaden des Projekts.
  2. Schreib ins Issue, dass du es übernimmst — das erspart doppelte Arbeit.
  3. Forke das Repository und arbeite in einem Branch.
  4. Öffne einen Pull Request, der die Issue-Nummer nennt.

Rechercherichtung

Beginne damit, die in diesem Issue vorgeschlagenen Operatoren und das Phantom-Typ-Modell zu lesen, und vergleiche dann die verlinkten Mongoose-Beispiele und das zugehörige Issue #28699. Identifiziere die TypeScript-Compiler-Einstiegspunkte für bedingte Typen und Typmodifizierer, bevor du das beabsichtigte Verhalten für Unions, Records, Arrays, Klassen und benutzerdefinierte Phantom-Metadaten definierst. Als erledigt gilt die Arbeit, wenn ein festgelegtes Design und die entsprechenden Compiler-Tests vorliegen.

Vom Indexierungsmodell aus dem Issue-Text verfasst.

Bewertung

Tech-Stack
typescript
Bereich
compilers
Issue-Typ
Feature
Schwierigkeit
5/5
Geschätzter Aufwand
Über eine Woche
Aktivitätsstatus
Veraltet
Klarheit
Muss geklärt werden
Anfängerfreundlichkeit
15/100

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