SameAsForResourceInField Policy

This policy looks at a given field of type single-reference and applies policy
logic from policy attached to the item referenced by that field's value.

Constructor params

Takes only one constructor param, an object with keys:

• collection_name: string - due to implementation quirks, you have to specify manually the name of the collection that this policy is attached to. For example, if this policy is attached to collection users, pass "users" in here.
• field: string - which field to look at when finding the item. It has to be a field of type single-reference.
• action: ActionName(string): once the referenced item is found, a policy for this action will be extracted from it. Example: "show", "list", "edit", "create"

Example

Below code creates an app that allows comments under a given photo to be visible
only to users who can see the given photo. Changing the policy for photos will
automatically influence the policy for comments.

const app = new (class extends App {
    config = {
        /* ... */
    };
    manifest = {
        /* ... */
    };
    collections = {
        ...App.BaseCollections,
        photos: new (class extends Collection {
            fields = {
                photo: new FieldTypes.Image(),
            };
            defaultPolicy = new Policies.Owner();
        })(),
        comments: new (class extends Collection {
            fields = {
                photo: new FieldTypes.SingleReference("photos"),
                content: new FieldTypes.Text(),
            };
            policies = {
                show: new Policies.SameAsForResourceInField({
                    collection_name: "comments",
                    field: "photo",
                    action_name: "show",
                }),
            };
        })(),
    };
})();