Querying the state of the grid

[grancalavera]

We have some use cases where we need to interrogate the grid for its internal state. At the moment we are using a solution that looks like this:

import { createSnapshotHook, createHook } from 'grid-hook-component'

const hook =  createHook(callback)

function callback(rows, columns) {
  // some side effect
}

myGrid.use( createSnapshotHook().hook(hook) )

Then further down in our application we can request a snapshot at any time, and it will be handled by the hook's callback:

hook.requestSnapshot()

In #7 we discussed this might make more sense to do at the grid level. Is that the case? I think it might be a good idea to implement it as a component. I can see at least 2 use cases for a hook component:

1. You can define many different hooks and pass them to the grid to query the state at different times
2. You can define a single hook and process in many different ways (ala middleware) by several consumer.

Thoughts?