### toHash

Reduces a given Array-like into a value hash (keyed data store).

Given an Iterable or Array-like structure, call `Array.prototype.reduce.call()` on the provided object to step over it and return an Object, keyed by the reference value.

```js
const toHash = ( object, key ) =>
  Array.prototype.reduce.call( object, ( acc, data, index ) => ( ( acc[ !key ? index : data[ key ] ] = data ), acc ), {} )
```

```js
toHash([ 4,3,2,1 ]); // { 0: 4, 1: 3, 2: 2, 1: 1 }
toHash([ { a: 'label' } ], 'a'); // { label: { a: 'label' } }
// A more in depth example:
let users = [ { id: 1, first: 'Jon' }, { id: 2, first: 'Joe' }, { id: 3, first: 'Moe' } ];
let managers = [ { manager: 1, employees: [ 2, 3 ] } ];
// We use function here because we want a bindable reference, but a closure referencing the hash would work, too.
managers.forEach( manager =>
  manager.employees = manager.employees.map(
    function( id ){
      return this[id];
    },
    toHash( users, 'id' )
  )
);
managers; // [ { manager:1, employees: [ { id: 2, first: "Joe" }, { id: 3, first: "Moe" } ] } ]
```