Global access to state/actions in actions/components

[jason-whitted]

Slices are convenient when they are helping you out, but they very frequently impede the developer from being able to accomplish a goal. This is a recurring theme as seen in:

• How to call an action in a different slice from a nested asynchronous action #601 - @spapas was requesting global access to actions in an action
• Add connected components #604 - connected components, which make global access to state/actions available in components
• Lazy components #606 - @frenzzy commenting on possibly adding state/actions to every component's arguments

I have experimented with hyperapp over at etalisoft/hyperapp-extended to get this to work.

It modifies the following signatures:

// action signature
value => (state, actions, current) => ...
// component signature
(attributes, children, current) => ...

current is an object with the following methods:

• getState() - returns the global state
• getActions() returns the global actions

This allows both actions and components the flexibility to have access to current state/actions even in nested async callbacks.

The current object is only created once and frozen and merely passed along as an additional argument, which should have no negative performance impact.

[jorgebucaran]

Closed in favor of #606.