[change] allow to customize the react-modal document.body open class.

This is a backport of @cassln's feature to version 1.8.x.

Author: diasbruno

Diff for: docs/README.md

@@ -52,6 +52,11 @@ import ReactModal from 'react-modal';
      See the `Styles` section for more details.
   */
   className="ReactModal__Content"
+  /*
+     String className to be applied to the document.body.
+     See the `Styles` section for more details.
+  */
+  bodyOpenClassName="ReactModal__Body--open"
   /*
     Boolean indicating if the appElement should be hidden
   */

Diff for: docs/styles/classes.md

@@ -1,5 +1,6 @@
 ### CSS Classes
 
 Sometimes it may be preferable to use CSS classes rather than inline styles.  You can use the `className` and `overlayClassName` props to specify a given CSS class for each of those.
+You can override the default class that is added to `document.body` when the modal is open by defining a property `bodyOpenClassName`.
 Note: If you provide those props all default styles will not be applied, leaving all styles under control of the CSS class.
 The `portalClassName` can also be used however there are no styles by default applied

Diff for: lib/components/Modal.js

@@ -38,6 +38,7 @@ var Modal = createReactClass({
       overlay: PropTypes.object
     }),
     portalClassName: PropTypes.string,
+    bodyOpenClassName: React.PropTypes.string,
     appElement: PropTypes.instanceOf(SafeHTMLElement),
     onAfterOpen: PropTypes.func,
     onRequestClose: PropTypes.func,
@@ -53,6 +54,7 @@ var Modal = createReactClass({
     return {
       isOpen: false,
       portalClassName: 'ReactModalPortal',
+      bodyOpenClassName: 'ReactModal__Body--open',
       ariaHideApp: true,
       closeTimeoutMS: 0,
       shouldCloseOnOverlayClick: true,
@@ -114,16 +116,17 @@ var Modal = createReactClass({
     ReactDOM.unmountComponentAtNode(this.node);
     var parent = getParentElement(this.props.parentSelector);
     parent.removeChild(this.node);
+
     if (refCount.count() === 0) {
-      elementClass(document.body).remove('ReactModal__Body--open');
+      elementClass(document.body).remove(this.props.bodyOpenClassName);
     }
   },
 
   renderPortal: function(props) {
     if (props.isOpen || refCount.count() > 0) {
-      elementClass(document.body).add('ReactModal__Body--open');
+      elementClass(document.body).add(this.props.bodyOpenClassName);
     } else {
-      elementClass(document.body).remove('ReactModal__Body--open');
+      elementClass(document.body).remove(this.props.bodyOpenClassName);
     }
 
     if (props.ariaHideApp) {

Diff for: specs/Modal.spec.js

@@ -171,6 +171,11 @@ describe('State', () => {
     ).toBeTruthy();
   });
 
+  it('supports overriding react modal open class in document.body.', () => {
+    const modal = renderModal({ isOpen: true, bodyOpenClassName: 'custom-modal-open' });
+    expect(document.body.className.indexOf('custom-modal-open') !== -1).toBeTruthy();
+  });
+
   it('don\'t append class to document.body if modal is not open', () => {
     renderModal({ isOpen: false });
     expect(!isBodyWithReactModalOpenClass()).toBeTruthy();