how to give object class to the function-CodePudding

Here is the code

copy-pasted code:

const check = async <Entity>(

      ) => {
        if (ObjectUtil.areChanged(memberUser.client, data, 'employmentTypeId')) {
          const beforeEmploymentType = await manager.findOneOrFail(Entity, memberUser.client.employmentTypeId);
          const afterEmploymentType = await manager.findOneOrFail(EmploymentType, data.employmentTypeId);
        }
      }

How can I add any object class to the function? It gives 'Entity' only refers to a type, but is being used as a value here.

CodePudding user response：

Since all types are erased after compilation, and so are type parameters (<Entity>), there's no such thing as Entity at runtime, so you cannot use it anywhere but in type annotations.

You need to pass it as a value to your function, like this:

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

I can't figure out a type for Entity parameter, because I cannot really tell what it is and how it's used from your example, but you can look for constructs like typeof MyClass to pass a class itself as a parameter, or { new(): MyClassInstance } for just something that can be called with new keyword. I've made some examples here.

CodePudding user response：

There is needed to add EntityTarget to implement any Entity class, it looks like:

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

So the using would be

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