Merge pull request #672 from Chalarangelo/skatcat31-patch-1

Add toHash snippet

snippets/toHash.md

@@ -0,0 +1,28 @@
+### 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" } ] } ]
+```