Discover the method for assigning an object class to a function

Question

Discover the method for assigning an object class to a function

Here is the code https://i.sstatic.net/zspmr.png

copy-pasted snippet:

const verifyEntity = async <ObjectClass>(

      ) => {
        if (ObjectUtil.areDifferent(user.client, info, 'typeId')) {
          const beforeType = await handler.retrieve(ObjectClass, user.client.typeId);
          const afterType = await manager.find(ObjectClass, info.typeId);
        }
      }

How do I incorporate any type of object into this function? I'm encountering an issue with

'ObjectClass' only refers to a type, but is being used as a value here.

typescript oop

Answer 1

Answer №1

After the code is compiled, all types are removed along with type parameters (<Entity>). This means that at runtime, there is no existence of Entity, making it unable to be used outside of type annotations.

To incorporate it into your function, you must pass it as a value like this:

const check = async (Entity: ???) => { ... }

Determining the type for the Entity parameter can be challenging without knowing its usage in your specific scenario. You may consider using constructs such as typeof MyClass to pass a class itself or { new(): MyClassInstance } for something callable with the new keyword. For some examples, refer to this link.

Answer 2

After the code is compiled, all types are removed along with type parameters (<Entity>). This means that at runtime, there is no existence of Entity, making it unable to be used outside of type annotations.

To incorporate it into your function, you must pass it as a value like this:

const check = async (Entity: ???) => { ... }

Determining the type for the Entity parameter can be challenging without knowing its usage in your specific scenario. You may consider using constructs such as typeof MyClass to pass a class itself or { new(): MyClassInstance } for something callable with the new keyword. For some examples, refer to this link.

Answer 3

Answer №2

To effectively implement any Entity class, it is necessary to include EntityTarget, as shown below:

const validate = async <Entity, A>(
    manager: EntityManager,
    entity: EntityTarget<Entity>,
    base: A,
    key: keyof A,
) => {
  const beforeEntity = await manager.findOneOrFail(entity, base[key]);
};

Therefore, the usage would be as follows:

await validate(manager, Room, booking, 'roomId');

Answer 4

To effectively implement any Entity class, it is necessary to include EntityTarget, as shown below:

const validate = async <Entity, A>(
    manager: EntityManager,
    entity: EntityTarget<Entity>,
    base: A,
    key: keyof A,
) => {
  const beforeEntity = await manager.findOneOrFail(entity, base[key]);
};

Therefore, the usage would be as follows:

await validate(manager, Room, booking, 'roomId');

Discover the method for assigning an object class to a function

Answer №1

Answer №2

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