Unexpected field access control behaviour in KeystoneJS

I am attempting to apply field level access logic in KeystoneJS, as per these instructions.

The following hides a field fieldName from the admin UI:

fieldName: {
  type: Text,
  access: {
    read: false,
    update: false,
    create: false
  },
},

But the field is not hidden from the admin UI if I use an imperative approach. See below, which I would expect to produce the same result as the static approach above:

fieldName: {
  type: Text,
  access: {
    read: ({ authentication: { item, listKey } }) => {
      return false;
    },
    update: ({ authentication: { item, listKey } }) => {
      return false;
    },
    create: ({ authentication: { item, listKey } }) => {
      return false;
    }
  },
},

Am I missing something or is this a bug?

Answer

Imperative approach uses a function which can not be transferred to the client side.

Keystone uses maybe true false value for this. this means !!(() => {}) becomes true when generating admin ui metadata for fields in list.

there is a note in the section “Granular Imperative Boolean” which explains that these fields indeed gets included in graphql and ui but are excluded during execution.