Add text directionality override prop to DraftEditor (facebookarchive…

…#1034)

* Add text directionality override prop to DraftEditor

Credit for this change goes to @mmmoussa

 - Added an optional textDirectionality prop of type
   DraftTextDirectionality to the DraftEditor component which allows
   overriding the directionality of all blocks in the editor.
 - Fixed lint errors in the modified Draft.js files.

Note that we will be updating the DraftTextDirectionality type
definition to move it to the `fbjs` shared utils, possibly along with
related text directionality utilities.

* Hold off on updating docs with textDirectionality

Since we haven't released this new prop yet let's not add it to the
documentation until we do.

* Use BidiDirection instead of own directionality type

Thanks to @zpao for pointing out that fbjs has BidiDirction.

src/component/base/DraftEditor.react.js

@@ -286,6 +286,7 @@ class DraftEditor extends React.Component {
               editorKey={this._editorKey}
               editorState={this.props.editorState}
               key={'contents' + this.state.contentsKey}
+              textDirectionality={this.props.textDirectionality}
             />
           </div>
         </div>

src/component/base/DraftEditorProps.js

@@ -12,6 +12,7 @@
 
 'use strict';
 
+import type {BidiDirection} from 'UnicodeBidiDirection';
 import type ContentBlock from 'ContentBlock';
 import type {DraftBlockRenderMap} from 'DraftBlockRenderMap';
 import type {DraftDragType} from 'DraftDragType';
@@ -51,6 +52,10 @@ export type DraftEditorProps = {
   // regardless of input characters.
   textAlignment?: DraftTextAlignment,
 
+  // Specify whether text directionality should be forced in a direction
+  // regardless of input characters.
+  textDirectionality?: BidiDirection,
+
   // For a given `ContentBlock` object, return an object that specifies
   // a custom block component and/or props. If no object is returned,
   // the default `TextEditorBlock` is used.

src/component/contents/DraftEditorContents.react.js

@@ -29,6 +29,7 @@ type Props = {
   blockRendererFn: Function,
   blockStyleFn: (block: ContentBlock) => string,
   editorState: EditorState,
+  textDirectionality?: BidiDirection,
 };
 
 /**
@@ -123,7 +124,10 @@ class DraftEditorContents extends React.Component {
         customEditable = customRenderer.editable;
       }
 
-      const direction = directionMap.get(key);
+      const {textDirectionality} = this.props;
+      const direction = textDirectionality
+        ? textDirectionality
+        : directionMap.get(key);
       const offsetKey = DraftOffsetKey.encode(key, 0, 0);
       const componentProps = {
         contentState: content,