refactor: cut down the component from SideNav component

browser/components/SideNavFilter.js

@@ -0,0 +1,41 @@
+/**
+ * @fileoverview Filter for all notes.
+ */
+import React, { PropTypes } from 'react'
+import CSSModules from 'browser/lib/CSSModules'
+import styles from './SideNavFilter.styl'
+
+/**
+ * @param {boolean} isHomeActive
+ * @param {Function} handleAllNotesButtonClick
+ * @param {boolean} isStarredActive
+ * @param {Function} handleStarredButtonClick
+ * @return {React.Component}
+ */
+const SideNavFilter = ({
+  isHomeActive, handleAllNotesButtonClick, isStarredActive, handleStarredButtonClick
+}) => (
+  <div styleName='menu'>
+    <button styleName={isHomeActive ? 'menu-button--active' : 'menu-button'}
+      onClick={handleAllNotesButtonClick}
+    >
+      <i className='fa fa-book fa-fw'/>
+      <span styleName='menu-button-label'>All Notes</span>
+    </button>
+    <button styleName={isStarredActive ? 'menu-button--active' : 'menu-button'}
+      onClick={handleStarredButtonClick}
+    >
+      <i className='fa fa-star fa-fw'/>
+      <span styleName='menu-button-label'>Starred</span>
+    </button>
+  </div>
+)
+
+SideNavFilter.propTypes = {
+  isHomeActive: PropTypes.bool.isRequired,
+  handleAllNotesButtonClick: PropTypes.func.isRequired,
+  isStarredActive: PropTypes.bool.isRequired,
+  handleStarredButtonClick: PropTypes.func.isRequired,
+}
+
+export default CSSModules(SideNavFilter, styles)

browser/components/SideNavFilter.styl

@@ -0,0 +1,32 @@
+.menu
+  margin-bottom 30px
+
+.menu-button
+  navButtonColor()
+  height 32px
+  padding 0 15px
+  font-size 14px
+  width 100%
+  text-align left
+  overflow ellipsis
+
+.menu-button--active
+  @extend .menu-button
+  background-color $ui-button--active-backgroundColor
+  color $ui-button--active-color
+  &:hover
+    background-color $ui-button--active-backgroundColor
+
+.menu-button-label
+  margin-left 5px
+
+body[data-theme="dark"]
+  .menu-button
+    navDarkButtonColor()
+
+  .menu-button--active
+    @extend .menu-button
+    background-color $ui-dark-button--active-backgroundColor
+    color $ui-dark-button--active-color
+    &:hover
+      background-color $ui-dark-button--active-backgroundColor