Add perf optimizations to Injector

src/Injector.js

@@ -1,5 +1,6 @@
 import { Component, PropTypes } from 'react';
 import mapValues from 'lodash/object/mapValues';
+import shallowEqual from './utils/shallowEqual';
 
 export default class Injector extends Component {
   static contextTypes = {
@@ -17,6 +18,15 @@ export default class Injector extends Component {
     actions: {}
   };
 
+  shouldComponentUpdate(nextProps, nextState) {
+    return this.hasChanged(this.state.atom, nextState.atom) ||
+           !shallowEqual(this.props.actions, nextProps.actions);
+  }
+
+  hasChanged(atom, prevAtom) {
+    return atom !== prevAtom;
+  }
+
   constructor(props, context) {
     super(props, context);
 

src/addons/inject.js

@@ -1,6 +1,7 @@
 import React from 'react';
 import Injector from '../Injector';
 import getDisplayName from '../utils/getDisplayName';
+import shallowEqualScalar from '../utils/shallowEqualScalar';
 
 function mergeAll({ props, state, actions }) {
   return { ...props, ...state, ...actions };
@@ -13,6 +14,10 @@ export default function inject(
   return DecoratedComponent => class InjectorDecorator {
     static displayName = `Injector(${getDisplayName(DecoratedComponent)})`;
 
+    shouldComponentUpdate(nextProps) {
+      return !shallowEqualScalar(this.props, nextProps);
+    }
+
     constructor() {
       this.renderChild = this.renderChild.bind(this);
     }