Use asynchronous logic for help completions (#1489)

Author: rjmholt

src/features/HelpCompletion.ts

@@ -54,7 +54,7 @@ export class HelpCompletionFeature implements IFeature {
         }
     }
 
-    public onEvent(changeEvent: TextDocumentChangeEvent): void {
+    public async onEvent(changeEvent: TextDocumentChangeEvent): Promise<void> {
         if (!(changeEvent && changeEvent.contentChanges)) {
             this.log.writeWarning(`<${HelpCompletionFeature.name}>: ` +
                 `Bad TextDocumentChangeEvent message: ${JSON.stringify(changeEvent)}`);
@@ -69,7 +69,8 @@ export class HelpCompletionFeature implements IFeature {
 
             // todo raise an event when trigger is found, and attach complete() to the event.
             if (this.helpCompletionProvider.triggerFound) {
-                this.helpCompletionProvider.complete().then(() => this.helpCompletionProvider.reset());
+                await this.helpCompletionProvider.complete();
+                await this.helpCompletionProvider.reset();
             }
         }
     }
@@ -156,36 +157,37 @@ class HelpCompletionProvider {
         this.triggerFinderHelpComment.reset();
     }
 
-    public complete(): Thenable<void> {
+    public async complete(): Promise<void> {
         if (this.langClient === undefined) {
             return;
         }
 
-        const change = this.lastChangeText;
         const triggerStartPos = this.lastChangeRange.start;
-        const triggerEndPos = this.lastChangeRange.end;
         const doc = this.lastDocument;
 
-        return this.langClient.sendRequest(
-            CommentHelpRequestType,
-            {
-                documentUri: doc.uri.toString(),
-                triggerPosition: triggerStartPos,
-                blockComment: this.settings.helpCompletion === Settings.HelpCompletion.BlockComment,
-            }).then((result) => {
-                if (result == null || result.content == null) {
-                    return;
-                }
+        const result = await this.langClient.sendRequest(CommentHelpRequestType, {
+            documentUri: doc.uri.toString(),
+            triggerPosition: triggerStartPos,
+            blockComment: this.settings.helpCompletion === Settings.HelpCompletion.BlockComment,
+        });
+
+        if (!(result && result.content)) {
+            return;
+        }
+
+        const replaceRange = new Range(triggerStartPos.translate(0, -1), triggerStartPos.translate(0, 1));
+
+        // TODO add indentation level to the help content
+        // Trim leading whitespace (used by the rule for indentation) as VSCode takes care of the indentation.
+        // Trim the last empty line and join the strings.
+        const lines: string[] = result.content;
+        const text = lines
+            .map((x) => (x as any).trimLeft())
+            .join(this.getEOL(doc.eol));
 
-                // todo add indentation level to the help content
-                const editor = window.activeTextEditor;
-                const replaceRange = new Range(triggerStartPos.translate(0, -1), triggerStartPos.translate(0, 1));
+        const snippetString = new SnippetString(text);
 
-                // Trim leading whitespace (used by the rule for indentation) as VSCode takes care of the indentation.
-                // Trim the last empty line and join the strings.
-                const text = result.content.map((x) => x.trimLeft()).slice(0, -1).join(this.getEOL(doc.eol));
-                editor.insertSnippet(new SnippetString(text), replaceRange);
-            });
+        window.activeTextEditor.insertSnippet(snippetString, replaceRange);
     }
 
     private getEOL(eol: EndOfLine): string {