Allow to clear highlights on blur

Author: krassowski

CHANGELOG.md

@@ -2,11 +2,16 @@
 
 ### `@krassowski/jupyterlab-lsp 2.1.2` (2020-12-XX)
 
+- features
+
+  - highlights can now be auto-removed from the cells/editors on blur (set `removeOnBlur` to `true` in settings) ([#446])
+
 - bug fixes
   - improved performance of completion and highlights by minimising the number of highlight requests and GUI redraws (token checking, debouncing, acting on a single response only) ([#433])
   - highlights now update after cell focus/blur events even if those do not trigger cursor movement ([#433])
 
 [#433]: https://github.com/krassowski/jupyterlab-lsp/issues/433
+[#446]: https://github.com/krassowski/jupyterlab-lsp/issues/446
 
 ### `@krassowski/jupyterlab-lsp 2.1.1` (2020-12-15)
 

atest/05_Features/Highlights.robot

@@ -43,6 +43,19 @@ Highlights are added after typing
     Press Keys    None    a
     Should Highlight Token    testa
 
+Highlights are removed when no cell is focused
+    Enter Cell Editor    1    line=2
+    # Remove when turned on
+    Configure JupyterLab Plugin    {"removeOnBlur": true}    plugin id=${HIGHLIGHTS PLUGIN ID}
+    Should Highlight Token    test
+    Blur Cell Editor    1
+    Should Not Highlight Any Tokens
+    # Do not remove when turned off
+    Configure JupyterLab Plugin    {"removeOnBlur": false}    plugin id=${HIGHLIGHTS PLUGIN ID}
+    Should Highlight Token    test
+    Blur Cell Editor    1
+    Should Highlight Token    test
+
 *** Keywords ***
 Should Not Highlight Any Tokens
     Page Should Not Contain    css:.cm-lsp-highlight
@@ -59,3 +72,7 @@ Should Not Highlight Token
 
 Setup Highlights Test
     Setup Notebook    Python    Highlights.ipynb
+
+Blur Cell Editor
+    [Arguments]    ${cell_nr}
+    Click Element    css:.jp-Cell:nth-child(${cell_nr}) .jp-InputPrompt

atest/Variables.robot

@@ -45,6 +45,7 @@ ${CM CURSORS}     css:.jp-MainAreaWidget:not(.lm-mod-hidden) .CodeMirror-cursors
 # settings
 ${LSP PLUGIN ID}    @krassowski/jupyterlab-lsp:plugin
 ${COMPLETION PLUGIN ID}    @krassowski/jupyterlab-lsp:completion
+${HIGHLIGHTS PLUGIN ID}    @krassowski/jupyterlab-lsp:highlights
 ${JUMP PLUGIN ID}    @krassowski/jupyterlab-lsp:jump_to
 ${DIAGNOSTICS PLUGIN ID}    @krassowski/jupyterlab-lsp:diagnostics
 ${CSS USER SETTINGS}    .jp-SettingsRawEditor-user

packages/jupyterlab-lsp/schema/highlights.json

@@ -10,6 +10,12 @@
       "type": "number",
       "default": 250,
       "description": "Number of milliseconds to delay sending out the highlights request to the language server; you can get better responsiveness adjusting this value, but setting it to zero can actually slow it down as the server might get overwhelmed when moving the cursor."
+    },
+    "removeOnBlur": {
+      "title": "Remove highlights on editor (e.g. cell) blur",
+      "type": "boolean",
+      "default": false,
+      "description": "Whether the highlights should disappear after the focus leaves the editor/cell"
     }
   },
   "jupyter.lab.shortcuts": []

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

@@ -65,11 +65,20 @@ export class HighlightsCM extends CodeMirrorIntegration {
       this.debounced_get_highlight = this.create_debouncer();
     });
     this.editor_handlers.set('cursorActivity', this.onCursorActivity);
-    this.editor_handlers.set('blur', this.onCursorActivity);
+    this.editor_handlers.set('blur', this.onBlur);
     this.editor_handlers.set('focus', this.onCursorActivity);
     super.register();
   }
 
+  protected onBlur = () => {
+    if (this.settings.composite.removeOnBlur) {
+      this.clear_markers();
+      this.last_token = null;
+    } else {
+      this.onCursorActivity().catch(console.warn);
+    }
+  };
+
   remove(): void {
     this.handleHighlight = null;
     this.onCursorActivity = null;