feat(server): provide folding ranges for inline templates

Following the embedded language support documentation, this commit provides
folding ranges for inline templates in typescript files.
This feature is provided in the language server so other editors that
use the @angular/language-server package can make use of the feature as
well.

https://code.visualstudio.com/api/language-extensions/embedded-languages

fixes #852

Author: atscott

BUILD.bazel

@@ -54,6 +54,7 @@ npm_package(
         ":node_modules/semver",
         ":node_modules/typescript",
         ":node_modules/vscode-jsonrpc",
+        ":node_modules/vscode-html-languageservice",
         ":node_modules/vscode-languageclient",
         ":node_modules/vscode-languageserver-protocol",
         ":node_modules/vscode-languageserver-types",

client/src/client.ts

@@ -151,7 +151,15 @@ export class AngularLanguageClient implements vscode.Disposable {
           }
 
           return angularCompletionsPromise;
-        }
+        },
+        provideFoldingRanges: async (
+            document: vscode.TextDocument, context: vscode.FoldingContext,
+            token: vscode.CancellationToken, next) => {
+          if (!(await this.isInAngularProject(document)) || document.languageId !== 'typescript') {
+            return null;
+          }
+          return next(document, context, token);
+        },
       }
     };
   }

integration/lsp/ivy_spec.ts

@@ -181,6 +181,38 @@ describe('Angular Ivy language server', () => {
     expect(targetUri).toContain('libs/post/src/lib/post.component.ts');
   });
 
+  it('provides folding ranges for inline templates', async () => {
+    openTextDocument(client, APP_COMPONENT, `
+import {Component, EventEmitter, Input, Output} from '@angular/core';
+
+@Component({
+  selector: 'my-app',
+  template: \`
+  <div>
+    <span>
+      Hello {{name}}
+    </span>
+  </div>\`,
+})
+export class AppComponent {
+  name = 'Angular';
+  @Input() appInput = '';
+  @Output() appOutput = new EventEmitter<string>();
+}`);
+    const languageServiceEnabled = await waitForNgcc(client);
+    expect(languageServiceEnabled).toBeTrue();
+    const response = await client.sendRequest(lsp.FoldingRangeRequest.type, {
+      textDocument: {
+        uri: APP_COMPONENT_URI,
+      },
+    }) as lsp.FoldingRange[];
+    expect(Array.isArray(response)).toBe(true);
+    // 1 folding range for the div, 1 for the span
+    expect(response.length).toEqual(2);
+    expect(response).toContain({startLine: 6, endLine: 9});
+    expect(response).toContain({startLine: 7, endLine: 8});
+  });
+
   describe('signature help', () => {
     it('should show signature help for an empty call', async () => {
       client.sendNotification(lsp.DidOpenTextDocumentNotification.type, {

package.json

@@ -248,6 +248,7 @@
     "tslint": "6.1.3",
     "tslint-eslint-rules": "5.4.0",
     "vsce": "1.100.1",
+    "vscode-html-languageservice": "^5.0.2",
     "vscode-languageserver-protocol": "3.16.0",
     "vscode-languageserver-textdocument": "1.0.7",
     "vscode-test": "1.6.1",
@@ -257,4 +258,4 @@
     "type": "git",
     "url": "https://github.com/angular/vscode-ng-language-service"
   }
-}
+}

server/BUILD.bazel

@@ -53,6 +53,8 @@ esbuild(
         "vscode-languageserver",
         "vscode-uri",
         "vscode-jsonrpc",
+        "vscode-languageserver-textdocument",
+        "vscode-html-languageservice",
     ],
     config = "esbuild.mjs",
     # Do not enable minification. It seems to break the extension on Windows (with WSL). See #1198.

server/package.json

@@ -16,11 +16,13 @@
   },
   "dependencies": {
     "@angular/language-service": "15.0.0-next.0",
+    "vscode-html-languageservice": "^5.0.2",
     "vscode-jsonrpc": "6.0.0",
     "vscode-languageserver": "7.0.0",
+    "vscode-languageserver-textdocument": "^1.0.7",
     "vscode-uri": "3.0.3"
   },
   "publishConfig": {
     "registry": "https://wombat-dressing-room.appspot.com"
   }
-}
+}

server/src/BUILD.bazel

@@ -11,7 +11,9 @@ ts_project(
         "//:node_modules/@angular/language-service",
         "//:node_modules/@types/node",
         "//:node_modules/typescript",
+        "//:node_modules/vscode-html-languageservice",
         "//:node_modules/vscode-languageserver",
+        "//:node_modules/vscode-languageserver-textdocument",
         "//:node_modules/vscode-uri",
         "//common",
     ],

server/src/embedded_support.ts

@@ -0,0 +1,116 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import * as ts from 'typescript';
+
+/**
+ * Takes a TS file and strips out all non-inline template content.
+ *
+ * This process is the same as what's done in the VSCode example for embedded languages.
+ *
+ * Note that the example below implements the support on the client side. This is done on the server
+ * side to enable language services in other editors to take advantage of this feature by depending
+ * on the @angular/language-server package.
+ *
+ * @see https://github.com/microsoft/vscode-extension-samples/blob/fdd3bb95ce8e38ffe58fc9158797239fdf5017f1/lsp-embedded-request-forwarding/client/src/embeddedSupport.ts#L131-L141
+ * @see https://code.visualstudio.com/api/language-extensions/embedded-languages
+ */
+export function getHTMLVirtualContent(documentText: string): string {
+  const sf =
+      ts.createSourceFile('temp', documentText, ts.ScriptTarget.ESNext, true /* setParentNodes */);
+  const inlineTemplateNodes: ts.Node[] = findAllMatchingNodes(sf, isInlineTemplateNode);
+
+  // Create a blank document with same text length
+  let content = documentText.split('\n')
+                    .map(line => {
+                      return ' '.repeat(line.length);
+                    })
+                    .join('\n');
+
+  // add back all the inline template regions in-place
+  inlineTemplateNodes.forEach(r => {
+    content = content.slice(0, r.getStart(sf) + 1) +
+        documentText.slice(r.getStart(sf) + 1, r.getEnd() - 1) + content.slice(r.getEnd() - 1);
+  });
+  return content;
+}
+
+function isInlineTemplateNode(node: ts.Node) {
+  const assignment = getPropertyAssignmentFromValue(node, 'template');
+  return ts.isStringLiteralLike(node) && assignment !== null &&
+      getClassDeclFromDecoratorProp(assignment) !== null;
+}
+
+/**
+ * Returns a property assignment from the assignment value if the property name
+ * matches the specified `key`, or `null` if there is no match.
+ */
+export function getPropertyAssignmentFromValue(value: ts.Node, key: string): ts.PropertyAssignment|
+    null {
+  const propAssignment = value.parent;
+  if (!propAssignment || !ts.isPropertyAssignment(propAssignment) ||
+      propAssignment.name.getText() !== key) {
+    return null;
+  }
+  return propAssignment;
+}
+
+/**
+ * Given a decorator property assignment, return the ClassDeclaration node that corresponds to the
+ * directive class the property applies to.
+ * If the property assignment is not on a class decorator, no declaration is returned.
+ *
+ * For example,
+ *
+ * @Component({
+ *   template: '<div></div>'
+ *   ^^^^^^^^^^^^^^^^^^^^^^^---- property assignment
+ * })
+ * class AppComponent {}
+ *           ^---- class declaration node
+ *
+ * @param propAsgnNode property assignment
+ */
+export function getClassDeclFromDecoratorProp(propAsgnNode: ts.PropertyAssignment):
+    ts.ClassDeclaration|undefined {
+  if (!propAsgnNode.parent || !ts.isObjectLiteralExpression(propAsgnNode.parent)) {
+    return;
+  }
+  const objLitExprNode = propAsgnNode.parent;
+  if (!objLitExprNode.parent || !ts.isCallExpression(objLitExprNode.parent)) {
+    return;
+  }
+  const callExprNode = objLitExprNode.parent;
+  if (!callExprNode.parent || !ts.isDecorator(callExprNode.parent)) {
+    return;
+  }
+  const decorator = callExprNode.parent;
+  if (!decorator.parent || !ts.isClassDeclaration(decorator.parent)) {
+    return;
+  }
+  const classDeclNode = decorator.parent;
+  return classDeclNode;
+}
+
+export function findAllMatchingNodes(
+    sf: ts.SourceFile, filter: (node: ts.Node) => boolean): ts.Node[] {
+  const results: ts.Node[] = [];
+  const stack: ts.Node[] = [sf];
+
+  while (stack.length > 0) {
+    const node = stack.pop()!;
+
+    if (filter(node)) {
+      results.push(node);
+    } else {
+      stack.push(...node.getChildren());
+    }
+  }
+
+  return results;
+}

server/src/session.ts

@@ -9,6 +9,8 @@
 import {isNgLanguageService, NgLanguageService, PluginConfig} from '@angular/language-service/api';
 import * as ts from 'typescript/lib/tsserverlibrary';
 import {promisify} from 'util';
+import {getLanguageService as getHTMLLanguageService} from 'vscode-html-languageservice';
+import {TextDocument} from 'vscode-languageserver-textdocument';
 import * as lsp from 'vscode-languageserver/node';
 
 import {ServerOptions} from '../../common/initialize';
@@ -17,6 +19,7 @@ import {GetComponentsWithTemplateFile, GetTcbParams, GetTcbRequest, GetTcbRespon
 
 import {readNgCompletionData, tsCompletionEntryToLspCompletionItem} from './completion';
 import {tsDiagnosticToLspDiagnostic} from './diagnostic';
+import {getHTMLVirtualContent} from './embedded_support';
 import {resolveAndRunNgcc} from './ngcc';
 import {ServerHost} from './server_host';
 import {filePathToUri, getMappedDefinitionInfo, isConfiguredProject, isDebugMode, lspPositionToTsPosition, lspRangeToTsPositions, MruTracker, tsDisplayPartsToText, tsFileTextChangesToLspWorkspaceEdit, tsTextSpanToLspRange, uriToFilePath} from './utils';
@@ -51,6 +54,8 @@ enum NgccErrorMessageAction {
 const defaultFormatOptions: ts.FormatCodeSettings = {};
 const defaultPreferences: ts.UserPreferences = {};
 
+const htmlLS = getHTMLLanguageService();
+
 /**
  * Session is a wrapper around lsp.IConnection, with all the necessary protocol
  * handlers installed for Angular language service.
@@ -190,6 +195,7 @@ export class Session {
     conn.onRenameRequest(p => this.onRenameRequest(p));
     conn.onPrepareRename(p => this.onPrepareRename(p));
     conn.onHover(p => this.onHover(p));
+    conn.onFoldingRanges(p => this.onFoldingRanges(p));
     conn.onCompletion(p => this.onCompletion(p));
     conn.onCompletionResolve(p => this.onCompletionResolve(p));
     conn.onRequest(GetComponentsWithTemplateFile, p => this.onGetComponentsWithTemplateFile(p));
@@ -710,6 +716,7 @@ export class Session {
     this.clientCapabilities = params.capabilities;
     return {
       capabilities: {
+        foldingRangeProvider: true,
         codeLensProvider: this.ivy ? {resolveProvider: true} : undefined,
         textDocumentSync: lsp.TextDocumentSyncKind.Incremental,
         completionProvider: {
@@ -854,6 +861,23 @@ export class Session {
     }
   }
 
+  private onFoldingRanges(params: lsp.FoldingRangeParams) {
+    if (!params.textDocument.uri?.endsWith('ts')) {
+      return null;
+    }
+
+    const lsInfo = this.getLSAndScriptInfo(params.textDocument);
+    if (lsInfo === null) {
+      return;
+    }
+    const {scriptInfo} = lsInfo;
+    const docText = scriptInfo.getSnapshot().getText(0, scriptInfo.getSnapshot().getLength());
+    const virtualHtmlDocContents = getHTMLVirtualContent(docText);
+    const virtualHtmlDoc =
+        TextDocument.create(params.textDocument.uri.toString(), 'html', 0, virtualHtmlDocContents);
+    return htmlLS.getFoldingRanges(virtualHtmlDoc);
+  }
+
   private onDefinition(params: lsp.TextDocumentPositionParams): lsp.LocationLink[]|null {
     const lsInfo = this.getLSAndScriptInfo(params.textDocument);
     if (lsInfo === null) {

yarn.lock

@@ -7573,6 +7573,16 @@ [email protected]:
     yauzl "^2.3.1"
     yazl "^2.2.2"
 
+vscode-html-languageservice@^5.0.2:
+  version "5.0.2"
+  resolved "https://registry.yarnpkg.com/vscode-html-languageservice/-/vscode-html-languageservice-5.0.2.tgz#a66cb9d779f3094a8d14dd3a8f7935748435fd2a"
+  integrity sha512-TQmeyE14Ure/w/S+RV2IItuRWmw/i1QaS+om6t70iHCpamuTTWnACQPMSltVGm/DlbdyMquUePJREjd/h3AVkQ==
+  dependencies:
+    vscode-languageserver-textdocument "^1.0.7"
+    vscode-languageserver-types "^3.17.2"
+    vscode-nls "^5.2.0"
+    vscode-uri "^3.0.4"
+
 [email protected]:
   version "6.0.0"
   resolved "https://registry.yarnpkg.com/vscode-jsonrpc/-/vscode-jsonrpc-6.0.0.tgz#108bdb09b4400705176b957ceca9e0880e9b6d4e"
@@ -7595,7 +7605,7 @@ [email protected]:
     vscode-jsonrpc "6.0.0"
     vscode-languageserver-types "3.16.0"
 
-[email protected]:
+[email protected], vscode-languageserver-textdocument@^1.0.7:
   version "1.0.7"
   resolved "https://registry.yarnpkg.com/vscode-languageserver-textdocument/-/vscode-languageserver-textdocument-1.0.7.tgz#16df468d5c2606103c90554ae05f9f3d335b771b"
   integrity sha512-bFJH7UQxlXT8kKeyiyu41r22jCZXG8kuuVVA33OEJn1diWOZK5n8zBSPZFHVBOu8kXZ6h0LIRhf5UnCo61J4Hg==
@@ -7605,13 +7615,23 @@ [email protected]:
   resolved "https://registry.yarnpkg.com/vscode-languageserver-types/-/vscode-languageserver-types-3.16.0.tgz#ecf393fc121ec6974b2da3efb3155644c514e247"
   integrity sha512-k8luDIWJWyenLc5ToFQQMaSrqCHiLwyKPHKPQZ5zz21vM+vIVUSvsRpcbiECH4WR88K2XZqc4ScRcZ7nk/jbeA==
 
+vscode-languageserver-types@^3.17.2:
+  version "3.17.2"
+  resolved "https://registry.yarnpkg.com/vscode-languageserver-types/-/vscode-languageserver-types-3.17.2.tgz#b2c2e7de405ad3d73a883e91989b850170ffc4f2"
+  integrity sha512-zHhCWatviizPIq9B7Vh9uvrH6x3sK8itC84HkamnBWoDFJtzBf7SWlpLCZUit72b3os45h6RWQNC9xHRDF8dRA==
+
 [email protected]:
   version "7.0.0"
   resolved "https://registry.yarnpkg.com/vscode-languageserver/-/vscode-languageserver-7.0.0.tgz#49b068c87cfcca93a356969d20f5d9bdd501c6b0"
   integrity sha512-60HTx5ID+fLRcgdHfmz0LDZAXYEV68fzwG0JWwEPBode9NuMYTIxuYXPg4ngO8i8+Ou0lM7y6GzaYWbiDL0drw==
   dependencies:
     vscode-languageserver-protocol "3.16.0"
 
+vscode-nls@^5.2.0:
+  version "5.2.0"
+  resolved "https://registry.yarnpkg.com/vscode-nls/-/vscode-nls-5.2.0.tgz#3cb6893dd9bd695244d8a024bdf746eea665cc3f"
+  integrity sha512-RAaHx7B14ZU04EU31pT+rKz2/zSl7xMsfIZuo8pd+KZO6PXtQmpevpq3vxvWNcrGbdmhM/rr5Uw5Mz+NBfhVng==
+
 vscode-oniguruma@^1.5.1:
   version "1.5.1"
   resolved "https://registry.yarnpkg.com/vscode-oniguruma/-/vscode-oniguruma-1.5.1.tgz#9ca10cd3ada128bd6380344ea28844243d11f695"
@@ -7649,6 +7669,11 @@ [email protected]:
   resolved "https://registry.yarnpkg.com/vscode-uri/-/vscode-uri-3.0.3.tgz#a95c1ce2e6f41b7549f86279d19f47951e4f4d84"
   integrity sha512-EcswR2S8bpR7fD0YPeS7r2xXExrScVMxg4MedACaWHEtx9ftCF/qHG1xGkolzTPcEmjTavCQgbVzHUIdTMzFGA==
 
+vscode-uri@^3.0.4:
+  version "3.0.6"
+  resolved "https://registry.yarnpkg.com/vscode-uri/-/vscode-uri-3.0.6.tgz#5e6e2e1a4170543af30151b561a41f71db1d6f91"
+  integrity sha512-fmL7V1eiDBFRRnu+gfRWTzyPpNIHJTc4mWnFkwBUmO9U3KPgJAmTx7oxi2bl/Rh6HLdU7+4C9wlj0k2E4AdKFQ==
+
 watchpack@^2.3.1:
   version "2.3.1"
   resolved "https://registry.yarnpkg.com/watchpack/-/watchpack-2.3.1.tgz#4200d9447b401156eeca7767ee610f8809bc9d25"