feat: expose placements from popper js (#115)

Author: DrDyne

example/multiple.jsx

@@ -1,7 +1,6 @@
 import React from 'react'
-import PopperJS from 'popper.js'
 import { Portal } from 'react-portal'
-import { Manager, Target, Popper, Arrow } from '../src/react-popper'
+import { Manager, Target, Popper, Arrow, placements } from '../src/react-popper'
 
 const modifiers = {
   customStyle: {
@@ -34,7 +33,7 @@ class MultipleExample extends React.Component {
             })
           }
         >
-          {PopperJS.placements.map(placement => (
+          {placements.map(placement => (
             <option key={placement} value={placement}>
               {placement}
             </option>

src/Popper.jsx

@@ -2,6 +2,8 @@ import { Component, createElement } from 'react'
 import PropTypes from 'prop-types'
 import PopperJS from 'popper.js'
 
+export const placements = PopperJS.placements
+
 class Popper extends Component {
   static contextTypes = {
     popperManager: PropTypes.object,
@@ -14,7 +16,7 @@ class Popper extends Component {
   static propTypes = {
     component: PropTypes.oneOfType([PropTypes.node, PropTypes.func]),
     innerRef: PropTypes.func,
-    placement: PropTypes.oneOf(PopperJS.placements),
+    placement: PropTypes.oneOf(placements),
     eventsEnabled: PropTypes.bool,
     modifiers: PropTypes.object,
     children: PropTypes.oneOfType([PropTypes.node, PropTypes.func]),

src/react-popper.js

@@ -1,4 +1,4 @@
 export Manager from './Manager'
 export Target from './Target'
-export Popper from './Popper'
+export Popper, { placements } from './Popper'
 export Arrow from './Arrow'