From 2c86086444f2b9977198ba20b20e0f2dae403120 Mon Sep 17 00:00:00 2001
From: Luke Barnard <lukeb@openmarket.com>
Date: Wed, 2 Aug 2017 10:51:34 +0100
Subject: [PATCH 1/2] Account for `\n` after each block

when converting from text offsets to selection state.

fixes vector-im/riot-web#4728
---
 src/RichText.js | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/src/RichText.js b/src/RichText.js
index c060565e2f..ff223525d4 100644
--- a/src/RichText.js
+++ b/src/RichText.js
@@ -201,10 +201,8 @@ export function selectionStateToTextOffsets(selectionState: SelectionState,
 export function textOffsetsToSelectionState({start, end}: SelectionRange,
                                             contentBlocks: Array<ContentBlock>): SelectionState {
     let selectionState = SelectionState.createEmpty();
-
-    for (let block of contentBlocks) {
-        let blockLength = block.getLength();
-
+    for (const block of contentBlocks) {
+        const blockLength = block.getLength();
         if (start !== -1 && start < blockLength) {
             selectionState = selectionState.merge({
                 anchorKey: block.getKey(),
@@ -212,9 +210,8 @@ export function textOffsetsToSelectionState({start, end}: SelectionRange,
             });
             start = -1;
         } else {
-            start -= blockLength;
+            start -= blockLength + 1;
         }
-
         if (end !== -1 && end <= blockLength) {
             selectionState = selectionState.merge({
                 focusKey: block.getKey(),
@@ -222,10 +219,9 @@ export function textOffsetsToSelectionState({start, end}: SelectionRange,
             });
             end = -1;
         } else {
-            end -= blockLength;
+            end -= blockLength + 1;
         }
     }
-
     return selectionState;
 }
 

From 1512aff326d41157c8861dd782163fd958569e39 Mon Sep 17 00:00:00 2001
From: Luke Barnard <lukeb@openmarket.com>
Date: Wed, 2 Aug 2017 11:06:02 +0100
Subject: [PATCH 2/2] Add comments

---
 src/RichText.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/RichText.js b/src/RichText.js
index ff223525d4..225a1c212a 100644
--- a/src/RichText.js
+++ b/src/RichText.js
@@ -210,7 +210,7 @@ export function textOffsetsToSelectionState({start, end}: SelectionRange,
             });
             start = -1;
         } else {
-            start -= blockLength + 1;
+            start -= blockLength + 1; // +1 to account for newline between blocks
         }
         if (end !== -1 && end <= blockLength) {
             selectionState = selectionState.merge({
@@ -219,7 +219,7 @@ export function textOffsetsToSelectionState({start, end}: SelectionRange,
             });
             end = -1;
         } else {
-            end -= blockLength + 1;
+            end -= blockLength + 1; // +1 to account for newline between blocks
         }
     }
     return selectionState;