Improve typing for update operation

[LouisPinsard]

Hello !

When doing an update operation it would be awesome to be forced to fill the fields that are used in the key attributes.
For instance given this schema for a User entity:

{
            pk: {type: 'string', value: '${_type}#'},
            sk: {type: 'string', value: '${_type}#${id}'},

            gs1pk: {type: 'string', value: '${_type}#'},
            gs1sk: {type: 'string', value: '${_type}#${id}'},
            renderConfiguration: {
                type: Object,
                schema: {
                    pages: {
                        type: Array,
                        items: {type: String},
                    },
                } as const,
            },
            name: {type: 'string'},
            email: {type: 'string'},
            id: {type: 'string', generate: 'ulid'},
        }

The update typing on the User model should force me to fill the id attribute.

It could be achived with something like this:

export type Templated<Template> =
  Template extends `${string}$\{${infer PartA}}${infer PartB}`
    ? PartA | Templated<PartB>
    : never;

export type ExtractCompositeKeyAttribute<T extends OneModel> =
  | Templated<T['PK']['value']>
  | Templated<T['SK']['value']>;

export type AttributeForUpdate<T extends OneModel> = AttributeForGet<T> &
  Partial<Entity<T>>;

What do you think? Happy to try a PR if it seems right!

[mobsense]

Would be awesome if you could do a PR.

Be aware, that the TS magic is pretty fragile and you need to really test that we're not breaking other typings.

That being said, .... have at it.

Michael