feat(language-service): add definitions for templateUrl (#32238)

Adds support for `getDefinitionAt` when called on a templateUrl
property assignment.

The currrent architecture for getting definitions is designed to be
called on templates, so we have to introduce a new
`getTsDefinitionAndBoundSpan` method to get Angular-specific definitions
in TypeScript files and pass a `readTemplate` closure that will read the
contents of a template using `TypeScriptServiceHost#getTemplates`. We
can probably go in and make this nicer in a future PR, though I'm not
sure what the best architecture should be yet.

Part of angular/vscode-ng-language-service#111

PR Close #32238

integration/language_service_plugin/goldens/templateUrlDefinition.json

@@ -0,0 +1,32 @@
+{
+  "seq": 0,
+  "type": "response",
+  "command": "definitionAndBoundSpan",
+  "request_seq": 2,
+  "success": true,
+  "body": {
+    "definitions": [
+      {
+        "file": "${PWD}/project/app/widget.component.html",
+        "start": {
+          "line": 1,
+          "offset": 1
+        },
+        "end": {
+          "line": 1,
+          "offset": 1
+        }
+      }
+    ],
+    "textSpan": {
+      "start": {
+        "line": 5,
+        "offset": 17
+      },
+      "end": {
+        "line": 5,
+        "offset": 40
+      }
+    }
+  }
+}

integration/language_service_plugin/test.ts

@@ -1,21 +1,26 @@
-import { fork, ChildProcess } from 'child_process';
+import {ChildProcess, fork} from 'child_process';
 import {join} from 'path';
-import { Client } from './tsclient';
 import {goldenMatcher} from './matcher';
+import {Client} from './tsclient';
 
 describe('Angular Language Service', () => {
   jasmine.DEFAULT_TIMEOUT_INTERVAL = 10000; /* 10 seconds */
   const PWD = process.env.PWD !;
-  const SERVER_PATH = "./node_modules/typescript/lib/tsserver.js";
+  const SERVER_PATH = './node_modules/typescript/lib/tsserver.js';
   let server: ChildProcess;
   let client: Client;
 
   beforeEach(() => {
     jasmine.addMatchers(goldenMatcher);
-    server = fork(SERVER_PATH, [
-      '--logVerbosity', 'verbose',
-      '--logFile', join(PWD, 'tsserver.log'),
-    ], {
+    server = fork(
+        SERVER_PATH,
+        [
+          '--logVerbosity',
+          'verbose',
+          '--logFile',
+          join(PWD, 'tsserver.log'),
+        ],
+        {
           stdio: ['pipe', 'pipe', 'inherit', 'ipc'],
         });
     client = new Client(server);
@@ -35,13 +40,13 @@ describe('Angular Language Service', () => {
     });
     expect(response).toMatchGolden('configure.json');
     response = await client.sendRequest('compilerOptionsForInferredProjects', {
-      "options": {
-        module: "CommonJS",
-        target: "ES6",
+      'options': {
+        module: 'CommonJS',
+        target: 'ES6',
         allowSyntheticDefaultImports: true,
         allowNonTsExtensions: true,
         allowJs: true,
-        jsx: "Preserve"
+        jsx: 'Preserve'
       }
     });
     expect(response).toMatchGolden('compilerOptionsForInferredProjects.json');
@@ -52,10 +57,7 @@ describe('Angular Language Service', () => {
     });
     // Server does not send response to geterr request
     // https://github.com/Microsoft/TypeScript/blob/master/lib/protocol.d.ts#L1770
-    client.sendRequest('geterr', {
-      delay: 0,
-      files: [`${PWD}/project/app/app.module.ts`]
-    });
+    client.sendRequest('geterr', {delay: 0, files: [`${PWD}/project/app/app.module.ts`]});
   });
 
   it('should perform completions', async() => {
@@ -63,13 +65,13 @@ describe('Angular Language Service', () => {
       hostInfo: 'vscode',
     });
     await client.sendRequest('compilerOptionsForInferredProjects', {
-      "options": {
-        module: "CommonJS",
-        target: "ES6",
+      'options': {
+        module: 'CommonJS',
+        target: 'ES6',
         allowSyntheticDefaultImports: true,
         allowNonTsExtensions: true,
         allowJs: true,
-        jsx: "Preserve"
+        jsx: 'Preserve'
       }
     });
 
@@ -77,10 +79,7 @@ describe('Angular Language Service', () => {
       file: `${PWD}/project/app/app.component.ts`,
     });
 
-    client.sendRequest('geterr', {
-      delay: 0,
-      files: [`${PWD}/project/app/app.component.ts`]
-    });
+    client.sendRequest('geterr', {delay: 0, files: [`${PWD}/project/app/app.component.ts`]});
 
     client.sendRequest('change', {
       file: `${PWD}/project/app/app.component.ts`,
@@ -159,4 +158,23 @@ describe('Angular Language Service', () => {
     expect(resp2).toMatchGolden('definitionAndBoundSpan.json');
   });
 
+  it('should perform definitionAndBoundSpan for template URLs', async() => {
+    client.sendRequest('open', {
+      file: `${PWD}/project/app/widget.component.ts`,
+    });
+
+    const resp1 = await client.sendRequest('reload', {
+      file: `${PWD}/project/app/widget.component.ts`,
+      tmpFile: `${PWD}/project/app/widget.component.ts`,
+    }) as any;
+    expect(resp1.command).toBe('reload');
+    expect(resp1.success).toBe(true);
+
+    const resp2 = await client.sendRequest('definitionAndBoundSpan', {
+      file: `${PWD}/project/app/widget.component.ts`,
+      line: 5,
+      offset: 19,
+    });
+    expect(resp2).toMatchGolden('templateUrlDefinition.json');
+  });
 });

packages/language-service/src/definitions.ts

@@ -6,10 +6,13 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+import * as path from 'path';
 import * as ts from 'typescript'; // used as value and is provided at runtime
 import {AstResult} from './common';
 import {locateSymbol} from './locate_symbol';
-import {Span} from './types';
+import {getPropertyAssignmentFromValue, isClassDecoratorProperty} from './template';
+import {Span, TemplateSource} from './types';
+import {findTightestNode} from './utils';
 
 /**
  * Convert Angular Span to TypeScript TextSpan. Angular Span has 'start' and
@@ -59,3 +62,67 @@ export function getDefinitionAndBoundSpan(
       definitions, textSpan,
   };
 }
+
+/**
+ * Gets an Angular-specific definition in a TypeScript source file.
+ */
+export function getTsDefinitionAndBoundSpan(
+    sf: ts.SourceFile, position: number,
+    tsLsHost: Readonly<ts.LanguageServiceHost>): ts.DefinitionInfoAndBoundSpan|undefined {
+  const node = findTightestNode(sf, position);
+  if (!node) return;
+  switch (node.kind) {
+    case ts.SyntaxKind.StringLiteral:
+    case ts.SyntaxKind.NoSubstitutionTemplateLiteral:
+      // Attempt to extract definition of a URL in a property assignment.
+      return getUrlFromProperty(node as ts.StringLiteralLike, tsLsHost);
+    default:
+      return undefined;
+  }
+}
+
+/**
+ * Attempts to get the definition of a file whose URL is specified in a property assignment in a
+ * directive decorator.
+ * Currently applies to `templateUrl` properties.
+ */
+function getUrlFromProperty(
+    urlNode: ts.StringLiteralLike,
+    tsLsHost: Readonly<ts.LanguageServiceHost>): ts.DefinitionInfoAndBoundSpan|undefined {
+  const asgn = getPropertyAssignmentFromValue(urlNode);
+  if (!asgn) return;
+  // If the URL is not a property of a class decorator, don't generate definitions for it.
+  if (!isClassDecoratorProperty(asgn)) return;
+
+  const sf = urlNode.getSourceFile();
+  switch (asgn.name.getText()) {
+    case 'templateUrl':
+      // Extract definition of the template file specified by this `templateUrl` property.
+      const url = path.join(path.dirname(sf.fileName), urlNode.text);
+
+      // If the file does not exist, bail. It is possible that the TypeScript language service host
+      // does not have a `fileExists` method, in which case optimistically assume the file exists.
+      if (tsLsHost.fileExists && !tsLsHost.fileExists(url)) return;
+
+      const templateDefinitions: ts.DefinitionInfo[] = [{
+        kind: ts.ScriptElementKind.externalModuleName,
+        name: url,
+        containerKind: ts.ScriptElementKind.unknown,
+        containerName: '',
+        // Reading the template is expensive, so don't provide a preview.
+        textSpan: {start: 0, length: 0},
+        fileName: url,
+      }];
+
+      return {
+        definitions: templateDefinitions,
+        textSpan: {
+          // Exclude opening and closing quotes in the url span.
+          start: urlNode.getStart() + 1,
+          length: urlNode.getWidth() - 2,
+        },
+      };
+    default:
+      return undefined;
+  }
+}

packages/language-service/src/language_service.ts

@@ -10,7 +10,7 @@ import * as tss from 'typescript/lib/tsserverlibrary';
 
 import {isAstResult} from './common';
 import {getTemplateCompletions, ngCompletionToTsCompletionEntry} from './completions';
-import {getDefinitionAndBoundSpan} from './definitions';
+import {getDefinitionAndBoundSpan, getTsDefinitionAndBoundSpan} from './definitions';
 import {getDeclarationDiagnostics, getTemplateDiagnostics, ngDiagnosticToTsDiagnostic, uniqueBySpan} from './diagnostics';
 import {getHover} from './hover';
 import {Diagnostic, LanguageService} from './types';
@@ -80,6 +80,15 @@ class LanguageServiceImpl implements LanguageService {
     if (templateInfo) {
       return getDefinitionAndBoundSpan(templateInfo, position);
     }
+
+    // Attempt to get Angular-specific definitions in a TypeScript file, like templates defined
+    // in a `templateUrl` property.
+    if (fileName.endsWith('.ts')) {
+      const sf = this.host.getSourceFile(fileName);
+      if (sf) {
+        return getTsDefinitionAndBoundSpan(sf, position, this.host.host);
+      }
+    }
   }
 
   getHoverAt(fileName: string, position: number): tss.QuickInfo|undefined {

packages/language-service/src/typescript_host.ts

@@ -73,8 +73,7 @@ export class TypeScriptServiceHost implements LanguageServiceHost {
     ngModules: [],
   };
 
-  constructor(
-      private readonly host: ts.LanguageServiceHost, private readonly tsLS: ts.LanguageService) {
+  constructor(readonly host: ts.LanguageServiceHost, private readonly tsLS: ts.LanguageService) {
     this.summaryResolver = new AotSummaryResolver(
         {
           loadSummary(filePath: string) { return null; },

packages/language-service/test/definitions_spec.ts

@@ -254,6 +254,28 @@ describe('definitions', () => {
     }
   });
 
+  it('should be able to find a template from a url', () => {
+    const fileName = addCode(`
+      @Component({
+        templateUrl: './«test».ng',
+      })
+      export class MyComponent {}`);
+
+    const marker = getReferenceMarkerFor(fileName, 'test');
+    const result = ngService.getDefinitionAt(fileName, marker.start);
+
+    expect(result).toBeDefined();
+    const {textSpan, definitions} = result !;
+
+    expect(textSpan).toEqual({start: marker.start - 2, length: 9});
+
+    expect(definitions).toBeDefined();
+    expect(definitions !.length).toBe(1);
+    const [def] = definitions !;
+    expect(def.fileName).toBe('/app/test.ng');
+    expect(def.textSpan).toEqual({start: 0, length: 0});
+  });
+
   /**
    * Append a snippet of code to `app.component.ts` and return the file name.
    * There must not be any name collision with existing code.