Add autoCloseTag language service

Author: Andy Hanson

src/compiler/parser.ts

@@ -4147,27 +4147,6 @@ namespace ts {
             return finishNode(node);
         }
 
-        function tagNamesAreEquivalent(lhs: JsxTagNameExpression, rhs: JsxTagNameExpression): boolean {
-            if (lhs.kind !== rhs.kind) {
-                return false;
-            }
-
-            if (lhs.kind === SyntaxKind.Identifier) {
-                return (<Identifier>lhs).escapedText === (<Identifier>rhs).escapedText;
-            }
-
-            if (lhs.kind === SyntaxKind.ThisKeyword) {
-                return true;
-            }
-
-            // If we are at this statement then we must have PropertyAccessExpression and because tag name in Jsx element can only
-            // take forms of JsxTagNameExpression which includes an identifier, "this" expression, or another propertyAccessExpression
-            // it is safe to case the expression property as such. See parseJsxElementName for how we parse tag name in Jsx element
-            return (<PropertyAccessExpression>lhs).name.escapedText === (<PropertyAccessExpression>rhs).name.escapedText &&
-                tagNamesAreEquivalent((<PropertyAccessExpression>lhs).expression as JsxTagNameExpression, (<PropertyAccessExpression>rhs).expression as JsxTagNameExpression);
-        }
-
-
         function parseJsxElementOrSelfClosingElementOrFragment(inExpressionContext: boolean): JsxElement | JsxSelfClosingElement | JsxFragment {
             const opening = parseJsxOpeningOrSelfClosingElementOrOpeningFragment(inExpressionContext);
             let result: JsxElement | JsxSelfClosingElement | JsxFragment;
@@ -7906,4 +7885,25 @@ namespace ts {
         }
         return argMap;
     }
+
+    /** @internal */
+    export function tagNamesAreEquivalent(lhs: JsxTagNameExpression, rhs: JsxTagNameExpression): boolean {
+        if (lhs.kind !== rhs.kind) {
+            return false;
+        }
+
+        if (lhs.kind === SyntaxKind.Identifier) {
+            return (<Identifier>lhs).escapedText === (<Identifier>rhs).escapedText;
+        }
+
+        if (lhs.kind === SyntaxKind.ThisKeyword) {
+            return true;
+        }
+
+        // If we are at this statement then we must have PropertyAccessExpression and because tag name in Jsx element can only
+        // take forms of JsxTagNameExpression which includes an identifier, "this" expression, or another propertyAccessExpression
+        // it is safe to case the expression property as such. See parseJsxElementName for how we parse tag name in Jsx element
+        return (<PropertyAccessExpression>lhs).name.escapedText === (<PropertyAccessExpression>rhs).name.escapedText &&
+            tagNamesAreEquivalent((<PropertyAccessExpression>lhs).expression as JsxTagNameExpression, (<PropertyAccessExpression>rhs).expression as JsxTagNameExpression);
+    }
 }

src/harness/fourslash.ts

@@ -2743,6 +2743,14 @@ Actual: ${stringify(fullActual)}`);
             }
         }
 
+        public verifyAutoCloseTag(map: { [markerName: string]: string | undefined }): void {
+            for (const markerName in map) {
+                this.goToMarker(markerName);
+                const actual = this.languageService.getAutoCloseTagAtPosition(this.activeFile.fileName, this.currentCaretPosition);
+                assert.equal(actual, map[markerName]);
+            }
+        }
+
         public verifyMatchingBracePosition(bracePosition: number, expectedMatchPosition: number) {
             const actual = this.languageService.getBraceMatchingAtPosition(this.activeFile.fileName, bracePosition);
 
@@ -4079,6 +4087,10 @@ namespace FourSlashInterface {
             this.state.verifyBraceCompletionAtPosition(this.negative, openingBrace);
         }
 
+        public autoCloseTag(map: { [markerName: string]: string | undefined }): void {
+            this.state.verifyAutoCloseTag(map);
+        }
+
         public isInCommentAtPosition(onlyMultiLineDiverges?: boolean) {
             this.state.verifySpanOfEnclosingComment(this.negative, onlyMultiLineDiverges);
         }

src/harness/harnessLanguageService.ts

@@ -509,6 +509,9 @@ namespace Harness.LanguageService {
         isValidBraceCompletionAtPosition(fileName: string, position: number, openingBrace: number): boolean {
             return unwrapJSONCallResult(this.shim.isValidBraceCompletionAtPosition(fileName, position, openingBrace));
         }
+        getAutoCloseTagAtPosition(): string | undefined {
+            throw new Error("Not supported on the shim.");
+        }
         getSpanOfEnclosingComment(fileName: string, position: number, onlyMultiLine: boolean): ts.TextSpan {
             return unwrapJSONCallResult(this.shim.getSpanOfEnclosingComment(fileName, position, onlyMultiLine));
         }

src/harness/unittests/session.ts

@@ -188,6 +188,7 @@ namespace ts.server {
 
         describe("onMessage", () => {
             const allCommandNames: CommandNames[] = [
+                CommandNames.AutoCloseTag,
                 CommandNames.Brace,
                 CommandNames.BraceFull,
                 CommandNames.BraceCompletion,

src/server/client.ts

@@ -552,6 +552,10 @@ namespace ts.server {
             return notImplemented();
         }
 
+        getAutoCloseTagAtPosition(_fileName: string, _position: number): string | undefined {
+            return notImplemented();
+        }
+
         getSpanOfEnclosingComment(_fileName: string, _position: number, _onlyMultiLine: boolean): TextSpan {
             return notImplemented();
         }

src/server/protocol.ts

@@ -6,6 +6,7 @@
 namespace ts.server.protocol {
     // NOTE: If updating this, be sure to also update `allCommandNames` in `harness/unittests/session.ts`.
     export const enum CommandTypes {
+        AutoCloseTag = "autoCloseTag",
         Brace = "brace",
         /* @internal */
         BraceFull = "brace-full",
@@ -890,6 +891,17 @@ namespace ts.server.protocol {
         openingBrace: string;
     }
 
+    export interface AutoCloseTagRequest extends FileLocationRequest {
+        readonly command: CommandTypes.AutoCloseTag;
+        readonly arguments: AutoCloseTagRequestArgs;
+    }
+
+    export interface AutoCloseTagRequestArgs extends FileLocationRequestArgs {}
+
+    export interface AutoCloseTagResponse extends Response {
+        readonly body: TextInsertion;
+    }
+
     /**
      * @deprecated
      * Get occurrences request; value of command field is

src/server/session.ts

@@ -818,6 +818,13 @@ namespace ts.server {
             return this.getDiagnosticsWorker(args, /*isSemantic*/ true, (project, file) => project.getLanguageService().getSuggestionDiagnostics(file), !!args.includeLinePosition);
         }
 
+        private getAutoCloseTag(args: protocol.AutoCloseTagRequestArgs): TextInsertion | undefined {
+            const { file, project } = this.getFileAndProject(args);
+            const position = this.getPositionInFile(args, file);
+            const tag = project.getLanguageService().getAutoCloseTagAtPosition(file, position);
+            return tag === undefined ? undefined : { newText: tag, caretOffset: 0 };
+        }
+
         private getDocumentHighlights(args: protocol.DocumentHighlightsRequestArgs, simplifiedResult: boolean): ReadonlyArray<protocol.DocumentHighlightsItem> | ReadonlyArray<DocumentHighlights> {
             const { file, project } = this.getFileAndProject(args);
             const position = this.getPositionInFile(args, file);
@@ -2130,6 +2137,9 @@ namespace ts.server {
                 this.projectService.reloadProjects();
                 return this.notRequired();
             },
+            [CommandNames.AutoCloseTag]: (request: protocol.AutoCloseTagRequest) => {
+                return this.requiredResponse(this.getAutoCloseTag(request.arguments));
+            },
             [CommandNames.GetCodeFixes]: (request: protocol.CodeFixRequest) => {
                 return this.requiredResponse(this.getCodeFixes(request.arguments, /*simplifiedResult*/ true));
             },

src/services/services.ts

@@ -2051,6 +2051,18 @@ namespace ts {
             return true;
         }
 
+        function getAutoCloseTagAtPosition(fileName: string, position: number): string | undefined {
+            const sourceFile = syntaxTreeCache.getCurrentSourceFile(fileName);
+            const token = findPrecedingToken(position, sourceFile);
+            if (!token) return undefined;
+            const element = token.kind === SyntaxKind.GreaterThanToken
+                ? isJsxOpeningElement(token.parent) ? token.parent.parent : undefined
+                : isJsxText(token) ? token.parent : undefined;
+            if (element && !tagNamesAreEquivalent(element.openingElement.tagName, element.closingElement.tagName)) {
+                return `</${element.openingElement.tagName.getText(sourceFile)}>`;
+            }
+        }
+
         function getSpanOfEnclosingComment(fileName: string, position: number, onlyMultiLine: boolean): TextSpan | undefined {
             const sourceFile = syntaxTreeCache.getCurrentSourceFile(fileName);
             const range = formatting.getRangeOfEnclosingComment(sourceFile, position, onlyMultiLine);
@@ -2283,6 +2295,7 @@ namespace ts {
             getFormattingEditsAfterKeystroke,
             getDocCommentTemplateAtPosition,
             isValidBraceCompletionAtPosition,
+            getAutoCloseTagAtPosition,
             getSpanOfEnclosingComment,
             getCodeFixesAtPosition,
             getCombinedCodeFix,

src/services/types.ts

@@ -323,6 +323,7 @@ namespace ts {
         getDocCommentTemplateAtPosition(fileName: string, position: number): TextInsertion | undefined;
 
         isValidBraceCompletionAtPosition(fileName: string, position: number, openingBrace: number): boolean;
+        getAutoCloseTagAtPosition(fileName: string, position: number): string | undefined;
 
         getSpanOfEnclosingComment(fileName: string, position: number, onlyMultiLine: boolean): TextSpan | undefined;
 

tests/baselines/reference/api/tsserverlibrary.d.ts

@@ -4556,6 +4556,7 @@ declare namespace ts {
         getFormattingEditsAfterKeystroke(fileName: string, position: number, key: string, options: FormatCodeOptions | FormatCodeSettings): TextChange[];
         getDocCommentTemplateAtPosition(fileName: string, position: number): TextInsertion | undefined;
         isValidBraceCompletionAtPosition(fileName: string, position: number, openingBrace: number): boolean;
+        getAutoCloseTagAtPosition(fileName: string, position: number): string | undefined;
         getSpanOfEnclosingComment(fileName: string, position: number, onlyMultiLine: boolean): TextSpan | undefined;
         toLineColumnOffset?(fileName: string, position: number): LineAndCharacter;
         getCodeFixesAtPosition(fileName: string, start: number, end: number, errorCodes: ReadonlyArray<number>, formatOptions: FormatCodeSettings, preferences: UserPreferences): ReadonlyArray<CodeFixAction>;
@@ -5506,6 +5507,7 @@ declare namespace ts.server {
  */
 declare namespace ts.server.protocol {
     enum CommandTypes {
+        AutoCloseTag = "autoCloseTag",
         Brace = "brace",
         BraceCompletion = "braceCompletion",
         GetSpanOfEnclosingComment = "getSpanOfEnclosingComment",
@@ -6175,6 +6177,15 @@ declare namespace ts.server.protocol {
          */
         openingBrace: string;
     }
+    interface AutoCloseTagRequest extends FileLocationRequest {
+        readonly command: CommandTypes.AutoCloseTag;
+        readonly arguments: AutoCloseTagRequestArgs;
+    }
+    interface AutoCloseTagRequestArgs extends FileLocationRequestArgs {
+    }
+    interface AutoCloseTagResponse extends Response {
+        readonly body: TextInsertion;
+    }
     /**
      * @deprecated
      * Get occurrences request; value of command field is
@@ -8463,6 +8474,7 @@ declare namespace ts.server {
         private getSyntacticDiagnosticsSync;
         private getSemanticDiagnosticsSync;
         private getSuggestionDiagnosticsSync;
+        private getAutoCloseTag;
         private getDocumentHighlights;
         private setCompilerOptionsForInferredProjects;
         private getProjectInfo;