Fixed a bug causing block data being over-written when pasted.

Summary:
there is a bug in Draft JS replace fragment logic where it replaces
block data directly with the fragment's block data. That causes things like
notice block loses it's data when pasted from other blocks.

The diff introduces a new parameter to allow the data on the block to be merged
instead of replaced. That way we could preserve the original data as well as
merging from the fragment's data (if available).

Note that in our use case, old data take precedence - for exmaple, if you paste
from a "note" notice to a "warning" notice, the resulting notice should still be
warning instead of "note".

Differential Revision: D16167295

fbshipit-source-id: 6e525d2263014e0666928077a71d9d406bd68143

Author: Tee Xie

src/model/modifier/DraftModifier.js

@@ -18,6 +18,7 @@ import type {DraftInlineStyle} from 'DraftInlineStyle';
 import type {DraftRemovalDirection} from 'DraftRemovalDirection';
 import type SelectionState from 'SelectionState';
 import type {Map} from 'immutable';
+import type {BlockDataMergeBehavior} from 'insertFragmentIntoContentState';
 
 const CharacterMetadata = require('CharacterMetadata');
 const ContentStateInlineStyle = require('ContentStateInlineStyle');
@@ -118,6 +119,7 @@ const DraftModifier = {
     contentState: ContentState,
     targetRange: SelectionState,
     fragment: BlockMap,
+    mergeBlockData?: BlockDataMergeBehavior = 'REPLACE_WITH_NEW_DATA',
   ): ContentState {
     const withoutEntities = removeEntitiesAtEdges(contentState, targetRange);
     const withoutText = removeRangeFromContentState(
@@ -129,6 +131,7 @@ const DraftModifier = {
       withoutText,
       withoutText.getSelectionAfter(),
       fragment,
+      mergeBlockData,
     );
   },
 

src/model/transaction/insertFragmentIntoContentState.js

@@ -26,20 +26,36 @@ const randomizeBlockMapKeys = require('randomizeBlockMapKeys');
 
 const {List} = Immutable;
 
+export type BlockDataMergeBehavior =
+  | 'REPLACE_WITH_NEW_DATA'
+  | 'MERGE_OLD_DATA_TO_NEW_DATA';
+
 const updateExistingBlock = (
   contentState: ContentState,
   selectionState: SelectionState,
   blockMap: BlockMap,
   fragmentBlock: BlockNodeRecord,
   targetKey: string,
   targetOffset: number,
+  mergeBlockData?: BlockDataMergeBehavior = 'REPLACE_WITH_NEW_DATA',
 ): ContentState => {
   const targetBlock = blockMap.get(targetKey);
   const text = targetBlock.getText();
   const chars = targetBlock.getCharacterList();
   const finalKey = targetKey;
   const finalOffset = targetOffset + fragmentBlock.getText().length;
 
+  let data = null;
+
+  switch (mergeBlockData) {
+    case 'MERGE_OLD_DATA_TO_NEW_DATA':
+      data = fragmentBlock.getData().merge(targetBlock.getData());
+      break;
+    case 'REPLACE_WITH_NEW_DATA':
+      data = fragmentBlock.getData();
+      break;
+  }
+
   const newBlock = targetBlock.merge({
     text:
       text.slice(0, targetOffset) +
@@ -50,7 +66,7 @@ const updateExistingBlock = (
       fragmentBlock.getCharacterList(),
       targetOffset,
     ),
-    data: fragmentBlock.getData(),
+    data,
   });
 
   return contentState.merge({
@@ -290,6 +306,7 @@ const insertFragmentIntoContentState = (
   contentState: ContentState,
   selectionState: SelectionState,
   fragmentBlockMap: BlockMap,
+  mergeBlockData?: BlockDataMergeBehavior = 'REPLACE_WITH_NEW_DATA',
 ): ContentState => {
   invariant(
     selectionState.isCollapsed(),
@@ -320,6 +337,7 @@ const insertFragmentIntoContentState = (
       fragment.first(),
       targetKey,
       targetOffset,
+      mergeBlockData,
     );
   }