feat(Injector): The inject property for Injectors can now resolve to …

…null/undefined.

The inject property for Injectors can now also resolve to a null or undefined.  This ends up in
nothing being injected into the Injectable target.  This allows you to wrap some logic within an
inject function to perhaps hide or show content for example.

src/Injectable.js

@@ -41,9 +41,11 @@ const Injectable = (WrappedComponent) => {
     }
 
     render() {
+      const keyed = keyedElements(`injected`, this.state.injected);
+
       return (
         <WrappedComponent
-          injected={keyedElements(`injected`, this.state.injected)}
+          injected={keyed}
           {...this.props}
         />
       );

src/Provider.js

@@ -1,5 +1,5 @@
 import { Children, Component, PropTypes } from 'react';
-import { compose, find, map, uniqBy, without, withoutAll } from './utils';
+import { compose, find, filter, map, uniqBy, without, withoutAll } from './utils';
 
 class InjectablesProvider extends Component {
   static childContextTypes = {
@@ -55,6 +55,7 @@ class InjectablesProvider extends Component {
     const { injectables, injections } = registration;
 
     const elements = compose(
+      filter(x => x !== null && x !== undefined),
       map(x => x.injector.getInjectElement()),
       uniqBy(`injectorId`)
     )(injections);

test/integration.test.js

@@ -4,15 +4,15 @@ import { expect } from 'chai';
 import $ from 'teaspoon';
 
 describeWithDOM(`Given an Injectables configuration`, () => {
+  const { Provider, Injectable, Injector } = require(`../src/index.js`);
+
   let InjectableHeader;
   let Layout;
   let HeaderInjectingSectionOne;
   let HeaderInjectingSectionTwo;
   let render;
 
   before(() => {
-    const { Provider, Injectable, Injector } = require(`../src/index.js`);
-
     render = elements => $(
       <Provider>
         {elements}
@@ -21,7 +21,6 @@ describeWithDOM(`Given an Injectables configuration`, () => {
 
     const Header = ({ injected }) => (
       <div id="Header">
-        <span>These are the injections:</span>
         {injected}
       </div>
     );
@@ -171,4 +170,27 @@ describeWithDOM(`Given an Injectables configuration`, () => {
       expect(actual).to.equal(expected, `The injected content was not found.`);
     });
   });
+
+  describe(`When rendering a null/undefined from an Injector`, () => {
+    it(`Then nothing should be rendered`, () => {
+      const NullInjector = Injector({
+        to: InjectableHeader,
+        inject: () => null
+      })(() => <noscript />);
+
+      const rendered = render(
+        <Layout>
+          <NullInjector />
+        </Layout>
+      );
+
+      const actual = rendered
+        .find($.s`${InjectableHeader}`)
+        .find(`div[id=Header]`)
+        .children()
+        .length;
+
+      expect(actual).to.equal(0);
+    });
+  });
 });