Exo Composition: how to enhance an exo object with additional capabilities / methods?

[0xpatrickdev]

There is a JS convention where a with*() or enhance*() function takes an object and adds additional functionality to it:

const burger = { bread: true, tomato: true, patty: true };
const withCheese = foo => ({ ...foo, cheese: true });
const cheeseburger = withCheese(burger);

If I want to do the same with zone.exoClass() or zone.exoClassKit(), is this possible? Any gotchas I should look out for?

Edit, keywords for search: mixin, higher order function, compose, composition

[dckc]

briefly: use prepareGuardedAttenuator, which includes:

   * Create an exo object whose behavior is composed from a default target
   * and/or individual method override callbacks.

By way of example, myAddressNameAdmin adds a provideChild method to enhance the normal nameAdmin from prepareNameHubKit.

agoric-sdk/packages/vats/src/vat-provisioning.js

Line 20 in c5284e4

const mixinMyAddress = prepareMixinMyAddress(zone);