From b2592583c47a121f8f0401175e050b962c9589ff Mon Sep 17 00:00:00 2001
From: Bruno Windels <brunow@matrix.org>
Date: Fri, 24 May 2019 18:54:29 +0200
Subject: [PATCH] maintain caret at current line when position is on newline
 part

---
 src/editor/caret.js | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/src/editor/caret.js b/src/editor/caret.js
index 974c8802a4..5ff9dbc950 100644
--- a/src/editor/caret.js
+++ b/src/editor/caret.js
@@ -20,13 +20,23 @@ export function setCaretPosition(editor, model, caretPosition) {
     sel.removeAllRanges();
     const range = document.createRange();
     const {parts} = model;
+    const {index} = caretPosition;
+    let {offset} = caretPosition;
     let lineIndex = 0;
     let nodeIndex = -1;
-    for (let i = 0; i <= caretPosition.index; ++i) {
+    for (let i = 0; i <= index; ++i) {
         const part = parts[i];
         if (part && part.type === "newline") {
-            lineIndex += 1;
-            nodeIndex = -1;
+            if (i < index) {
+                lineIndex += 1;
+                nodeIndex = -1;
+            } else {
+                // if index points at a newline part,
+                // put the caret at the end of the previous part
+                // so it stays on the same line
+                const prevPart = parts[i - 1];
+                offset = prevPart ? prevPart.text.length : 0;
+            }
         } else {
             nodeIndex += 1;
         }
@@ -34,7 +44,7 @@ export function setCaretPosition(editor, model, caretPosition) {
     let focusNode;
     const lineNode = editor.childNodes[lineIndex];
     if (lineNode) {
-        if (lineNode.childNodes.length === 0 && caretPosition.offset === 0) {
+        if (lineNode.childNodes.length === 0 && offset === 0) {
             focusNode = lineNode;
         } else {
             focusNode = lineNode.childNodes[nodeIndex];
@@ -50,7 +60,7 @@ export function setCaretPosition(editor, model, caretPosition) {
         range.collapse(false);
     } else {
         // make sure we have a text node
-        range.setStart(focusNode, caretPosition.offset);
+        range.setStart(focusNode, offset);
         range.collapse(true);
     }
     sel.addRange(range);