Merge pull request #361 from krassowski/fix-syntax-updates

Fix performance issues caused by lazy syntax highlight implementation

Author: krassowski

CHANGELOG.md

@@ -1,5 +1,13 @@
 ## CHANGELOG
 
+### `@krassowski/jupyterlab-lsp 2.0.6` (unreleased)
+
+- bug fixes
+
+  - fix syntax highlighting of %%language cells slowing down editing in notebooks ([#361])
+
+[#361]: https://github.com/krassowski/jupyterlab-lsp/issues/361
+
 ### `@krassowski/jupyterlab-lsp 2.0.5` (2020-09-11)
 
 - bug fixes

packages/jupyterlab-lsp/src/features/syntax_highlighting.ts

@@ -75,7 +75,10 @@ export class CMSyntaxHighlighting extends CodeMirrorIntegration {
 
         // change the mode if the majority of the code is the foreign code
         if (coverage > this.settings.composite.foreignCodeThreshold) {
-          editor.setOption('mode', mode.mime);
+          let old_mode = editor.getOption('mode');
+          if (old_mode != mode.mime) {
+            editor.setOption('mode', mode.mime);
+          }
         }
       }
     }