feat: update editor directly to fix jumping cursor

manifest.json

@@ -7,5 +7,5 @@
   "isDesktopOnly": false,
   "minAppVersion": "0.15.0",
   "name": "Format Automatically with Prettier",
-  "version": "0.1.8"
+  "version": "0.2.0"
 }

package.json

@@ -1,13 +1,16 @@
 {
   "author": "Dylan Armstrong<dylan@dylan.is>",
   "dependencies": {
+    "diff-match-patch": "^1.0.5",
     "obsidian": "^1.8.7",
     "prettier": "^3.5.3"
   },
   "description": "This is a formatting plugin for Obsidian (https://obsidian.md)",
   "devDependencies": {
+    "@codemirror/view": "^6.36.8",
     "@dylanarmstrong/eslint-config": "^0.8.0",
     "@eslint/js": "^9.27.0",
+    "@types/diff-match-patch": "^1.0.36",
     "@types/node": "^22.15.21",
     "builtin-modules": "5.0.0",
     "esbuild": "0.25.4",

pnpm-lock.yaml

@@ -8,6 +8,9 @@ importers:
 
   .:
     dependencies:
+      diff-match-patch:
+        specifier: ^1.0.5
+        version: 1.0.5
       obsidian:
         specifier: ^1.8.7
         version: 1.8.7(@codemirror/state@6.5.2)(@codemirror/view@6.36.8)
@@ -15,12 +18,18 @@ importers:
         specifier: ^3.5.3
         version: 3.5.3
     devDependencies:
+      '@codemirror/view':
+        specifier: ^6.36.8
+        version: 6.36.8
       '@dylanarmstrong/eslint-config':
         specifier: ^0.8.0
         version: 0.8.0(eslint@9.27.0)
       '@eslint/js':
         specifier: ^9.27.0
         version: 9.27.0
+      '@types/diff-match-patch':
+        specifier: ^1.0.36
+        version: 1.0.36
       '@types/node':
         specifier: ^22.15.21
         version: 22.15.21
@@ -301,6 +310,9 @@ packages:
   '@types/codemirror@5.60.8':
     resolution: {integrity: sha512-VjFgDF/eB+Aklcy15TtOTLQeMjTo07k7KAjql8OK5Dirr7a6sJY4T1uVBDuTVG9VEmn1uUsohOpYnVfgC6/jyw==}
 
+  '@types/diff-match-patch@1.0.36':
+    resolution: {integrity: sha512-xFdR6tkm0MWvBfO8xXCSsinYxHcqkQUlcHeSpMC2ukzOb6lwQAfDmW+Qt0AvlGd8HpsS28qKsB+oPeJn9I39jg==}
+
   '@types/estree@1.0.7':
     resolution: {integrity: sha512-w28IoSUCJpidD/TGviZwwMJckNESJZXFu7NBZ5YJ4mEUnNraUn9Pm8HSZm/jDF1pDWYKspWE7oVphigUPRakIQ==}
 
@@ -454,6 +466,9 @@ packages:
   deep-is@0.1.4:
     resolution: {integrity: sha512-oIPzksmTg4/MriiaYGO+okXDT7ztn/w3Eptv/+gSIdMdKsJo0u4CfYNFJPy+4SKMuCqGw2wxnA+URMg3t8a/bQ==}
 
+  diff-match-patch@1.0.5:
+    resolution: {integrity: sha512-IayShXAgj/QMXgB0IWmKx+rOPuGMhqm5w6jvFxmVenXKIzRqTAAsbBPT3kWQeGANj3jGgvcvv4yK6SxqYmikgw==}
+
   electron-to-chromium@1.5.157:
     resolution: {integrity: sha512-/0ybgsQd1muo8QlnuTpKwtl0oX5YMlUGbm8xyqgDU00motRkKFFbUJySAQBWcY79rVqNLWIWa87BGVGClwAB2w==}
 
@@ -1036,6 +1051,8 @@ snapshots:
     dependencies:
       '@types/tern': 0.23.9
 
+  '@types/diff-match-patch@1.0.36': {}
+
   '@types/estree@1.0.7': {}
 
   '@types/json-schema@7.0.15': {}
@@ -1209,6 +1226,8 @@ snapshots:
 
   deep-is@0.1.4: {}
 
+  diff-match-patch@1.0.5: {}
+
   electron-to-chromium@1.5.157: {}
 
   esbuild@0.25.4:

src/@types/obsidian-ex.d.ts

@@ -1,4 +1,5 @@
 import 'obsidian';
+import { EditorView } from '@codemirror/view';
 
 declare module 'obsidian' {
   interface App {
@@ -12,6 +13,10 @@ declare module 'obsidian' {
     };
   }
 
+  interface Editor {
+    cm?: EditorView;
+  }
+
   interface Vault {
     getConfig(id: string): boolean;
   }

src/prettier-plugin.ts

@@ -1,3 +1,4 @@
+import DiffMatchPatch from 'diff-match-patch';
 import { EditorPosition, Plugin } from 'obsidian';
 
 import * as markdownPlugin from 'prettier/plugins/markdown';
@@ -17,22 +18,11 @@ const DEFAULT_SETTINGS: PrettierPluginSettings = {
   useTabs: true,
 };
 
-// Taken from https://github.com/alexgavrusev/obsidian-format-with-prettier/blob/master/src/cursor-position-utils.ts
-// If the cursor is on line i, on character j, the offset
-// is j plus sum of lengths (incl. the \n at the end) of lines 0..(i - 1)
-const toOffset = (position: EditorPosition, text: string): number =>
-  text
-    .split('\n')
-    .slice(0, position.line)
-    .reduce((accumulator, line) => accumulator + line.length + 1, position.ch);
-
-const fromOffset = (offset: number, text: string): EditorPosition => {
-  const textUpToOffset = text.slice(0, offset);
-  const newLines = textUpToOffset.split('\n');
-
+const getPosition = (text: string): EditorPosition => {
+  const lines = text.split('\n');
   return {
-    ch: newLines?.at(-1)?.length || 0,
-    line: newLines.length - 1,
+    ch: lines.at(-1)?.length ?? 0,
+    line: lines.length - 1,
   };
 };
 
@@ -43,28 +33,64 @@ export default class PrettierPlugin extends Plugin {
 
   private async format() {
     const editor = this.app.workspace.activeEditor?.editor;
-    if (!editor) {
+    if (!editor || !editor.cm) {
       return;
     }
 
     const file = this.app.workspace.getActiveFile();
     const text = editor.getValue();
     if (text && file) {
-      const position = editor.getCursor();
-      const cursorOffset = toOffset(position, text);
+      const formattedText = await prettier.format(text, {
+        embeddedLanguageFormatting: 'auto',
+        filepath: file.path,
+        parser: 'markdown',
+        plugins: [markdownPlugin],
+        tabWidth: this.settings.tabWidth,
+        useTabs: this.settings.useTabs,
+      });
 
-      const { cursorOffset: formattedCursorOffset, formatted: formattedText } =
-        await prettier.formatWithCursor(text, {
-          cursorOffset,
-          filepath: file.path,
-          parser: 'markdown',
-          plugins: [markdownPlugin],
-          tabWidth: this.settings.tabWidth,
-          useTabs: this.settings.useTabs,
-        });
+      // Switched to using DiffMatchPatch after I saw it here:
+      // https://github.com/platers/obsidian-linter
+      // And this style of updating the editor stops my cursor from jumping
+      // around. Also, it keeps sections toggled if I've closed them.
 
-      editor.setValue(formattedText);
-      editor.setCursor(fromOffset(formattedCursorOffset, formattedText));
+      // eslint-disable-next-line new-cap
+      const dmp = new DiffMatchPatch.diff_match_patch();
+      const changes = dmp.diff_main(text, formattedText);
+
+      let currentText = '';
+      for (const change of changes) {
+        const [type, value] = change;
+
+        if (type === DiffMatchPatch.DIFF_INSERT) {
+          editor.cm.dispatch({
+            changes: [
+              {
+                from: editor.posToOffset(getPosition(currentText)),
+                insert: value,
+              },
+            ],
+            filter: false,
+          });
+          currentText += value;
+        } else if (type === DiffMatchPatch.DIFF_DELETE) {
+          const start = getPosition(currentText);
+          const end = getPosition(currentText + value);
+
+          editor.cm.dispatch({
+            changes: [
+              {
+                from: editor.posToOffset(start),
+                insert: '',
+                to: editor.posToOffset(end),
+              },
+            ],
+            filter: false,
+          });
+        } else {
+          currentText += value;
+        }
+      }
     }
   }
 

tsconfig.json

@@ -1,6 +1,7 @@
 {
   "compilerOptions": {
     "allowJs": true,
+    "allowSyntheticDefaultImports": true,
     "baseUrl": ".",
     "importHelpers": true,
     "inlineSourceMap": true,