Defaulting Parameters

You may wish to provide default semantics to some of your action creator parameters. This too can be accomplished using the actionMeta.ratify property (ratifyFn()):

import {generateActions} from 'action-u';

const actions = generateActions({
  userMsg: {
              actionMeta: {
                traits: ['msg'],
                ratify: (msg='Hello action-u') => [msg]
              },
    close: {
              actionMeta: {}
    }
  }
});

NOTE: This is the reason ratifyFn() must return the arguments passed in: to allow it to inject default semantics. You should never attempt to return the built-in arguments array-like object for two reasons:

1. applied defaults are NOT reflected in arguments, and
2. arguments are not bound to arrow functions.

As you can see, the actionMeta.ratify function is used for both validation and default semantics. Here is an example employing both:

import {generateActions} from 'action-u';

const actions = generateActions({
  userMsg: {
              actionMeta: {
                traits: ['msg'],
                ratify(msg='Hello action-u')
                  assert(isString(msg), `ERROR: userMsg(msg) the supplied msg is NOT a string: ${msg}`);
                  return [msg];
                }
              },
    close: {
              actionMeta: {}
    }
  }
});