Reduce unnecessary inspects for same word (#87)

* Reduce unnecessary inspects for same word

* Throttling requests

src/contextualHelp/contextualHelp.ts

@@ -53,8 +53,11 @@ export class ContextualHelp extends WebviewViewHost<MessageMapping> implements v
         token: vscode.CancellationTokenSource;
         code: string;
         cursor_pos: number;
+        lineNumber: number;
         word: string;
+        wordAtPos: string;
         document: vscode.TextDocument;
+        timer?: NodeJS.Timeout;
     };
     public showHelp(editor: vscode.TextEditor) {
         // Code should be the entire cell
@@ -64,10 +67,13 @@ export class ContextualHelp extends WebviewViewHost<MessageMapping> implements v
         const cursor_pos = editor.document.offsetAt(editor.selection.active);
 
         // Word under cursor can be computed from the line
+        const lineNumber = editor.selection.active.line;
         const line = editor.document.lineAt(editor.selection.active.line).text;
         // Find first quote, parenthesis or space to the left
         let start = editor.selection.active.character;
         let end = editor.selection.active.character + 1;
+        const wordPos = editor.document.getWordRangeAtPosition(editor.selection.active);
+        const wordAtPos = wordPos ? editor.document.getText(wordPos) : '';
         let startFound = false;
         let endFound = false;
         while (!startFound || !endFound) {
@@ -83,28 +89,41 @@ export class ContextualHelp extends WebviewViewHost<MessageMapping> implements v
             }
         }
         const word = line.slice(start, end);
-        if (this.lastHelpRequest?.token) {
-            this.lastHelpRequest.token.cancel();
-        }
         if (
             this.lastHelpRequest?.code === code &&
-            this.lastHelpRequest?.cursor_pos === cursor_pos &&
-            this.lastHelpRequest?.word === word
+            (this.lastHelpRequest?.cursor_pos === cursor_pos || this.lastHelpRequest?.lineNumber === lineNumber) &&
+            this.lastHelpRequest?.word === word &&
+            this.lastHelpRequest?.wordAtPos === wordAtPos
         ) {
             return;
         }
+        if (this.lastHelpRequest?.token) {
+            this.lastHelpRequest.token.cancel();
+        }
+        if (this.lastHelpRequest?.timer) {
+            clearTimeout(this.lastHelpRequest.timer);
+        }
         const token = new vscode.CancellationTokenSource();
+        // lets wait a while before showing the help
+        // We need to wait for the user to stop typing before we show the help
+        // Or possible user is tabbing through cells/files, etc
+        const timer = setTimeout(() => {
+            // Make our inspect request
+            this.inspect(code, cursor_pos, word, editor.document, token.token).finally(() => {
+                token.dispose();
+            });
+        }, 300);
+
         this.lastHelpRequest = {
             code,
             cursor_pos,
             word,
+            lineNumber,
+            wordAtPos,
             document: editor.document,
-            token
+            token,
+            timer
         };
-        // Make our inspect request
-        this.inspect(code, cursor_pos, word, editor.document, token.token).finally(() => {
-            token.dispose();
-        });
     }
 
     public async load(codeWebview: vscode.WebviewView) {