Adopt prefer-readonly in JS/TS extension

.eslintignore

@@ -13,6 +13,8 @@
 **/extensions/notebook-renderers/renderer-out/index.js
 **/extensions/simple-browser/media/index.js
 **/extensions/typescript-language-features/test-workspace/**
+**/extensions/typescript-language-features/extension.webpack.config.js
+**/extensions/typescript-language-features/extension-browser.webpack.config.js
 **/extensions/vscode-api-tests/testWorkspace/**
 **/extensions/vscode-api-tests/testWorkspace2/**
 **/fixtures/**

extensions/typescript-language-features/.eslintrc.js

@@ -0,0 +1,10 @@
+module.exports = {
+	"parserOptions": {
+		"tsconfigRootDir": __dirname,
+		"project": "./tsconfig.json"
+	},
+	"rules": {
+		"@typescript-eslint/prefer-optional-chain": "warn",
+		"@typescript-eslint/prefer-readonly": "warn"
+	}
+};

extensions/typescript-language-features/src/experimentTelemetryReporter.ts

@@ -16,10 +16,11 @@ export interface IExperimentationTelemetryReporter extends tas.IExperimentationT
  * but will only do so when passed to an {@link ExperimentationService}.
  */
 
-export class ExperimentationTelemetryReporter
-	implements IExperimentationTelemetryReporter {
+export class ExperimentationTelemetryReporter implements IExperimentationTelemetryReporter {
+
 	private _sharedProperties: Record<string, string> = {};
-	private _reporter: VsCodeTelemetryReporter;
+	private readonly _reporter: VsCodeTelemetryReporter;
+
 	constructor(reporter: VsCodeTelemetryReporter) {
 		this._reporter = reporter;
 	}

extensions/typescript-language-features/src/experimentationService.ts

@@ -13,8 +13,8 @@ interface ExperimentTypes {
 }
 
 export class ExperimentationService {
-	private _experimentationServicePromise: Promise<tas.IExperimentationService>;
-	private _telemetryReporter: IExperimentationTelemetryReporter;
+	private readonly _experimentationServicePromise: Promise<tas.IExperimentationService>;
+	private readonly _telemetryReporter: IExperimentationTelemetryReporter;
 
 	constructor(telemetryReporter: IExperimentationTelemetryReporter, id: string, version: string, globalState: vscode.Memento) {
 		this._telemetryReporter = telemetryReporter;

extensions/typescript-language-features/src/languageFeatures/codeLens/baseCodeLensProvider.ts

@@ -36,7 +36,7 @@ export abstract class TypeScriptBaseCodeLensProvider implements vscode.CodeLensP
 
 	public constructor(
 		protected client: ITypeScriptServiceClient,
-		private cachedResponse: CachedResponse<Proto.NavTreeResponse>
+		private readonly cachedResponse: CachedResponse<Proto.NavTreeResponse>
 	) { }
 
 

extensions/typescript-language-features/src/languageFeatures/documentSymbol.ts

@@ -37,7 +37,7 @@ class TypeScriptDocumentSymbolProvider implements vscode.DocumentSymbolProvider
 
 	public constructor(
 		private readonly client: ITypeScriptServiceClient,
-		private cachedResponse: CachedResponse<Proto.NavTreeResponse>,
+		private readonly cachedResponse: CachedResponse<Proto.NavTreeResponse>,
 	) { }
 
 	public async provideDocumentSymbols(document: vscode.TextDocument, token: vscode.CancellationToken): Promise<vscode.DocumentSymbol[] | undefined> {

extensions/typescript-language-features/src/languageFeatures/fixAll.ts

@@ -185,7 +185,7 @@ class SourceAddMissingImports extends SourceAction {
 
 class TypeScriptAutoFixProvider implements vscode.CodeActionProvider {
 
-	private static kindProviders = [
+	private static readonly kindProviders = [
 		SourceFixAll,
 		SourceRemoveUnused,
 		SourceAddMissingImports,

extensions/typescript-language-features/src/protocol.d.ts

@@ -1,3 +1,7 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
 import * as ts from 'typescript/lib/tsserverlibrary';
 export = ts.server.protocol;
 

extensions/typescript-language-features/src/tsServer/serverProcess.browser.ts

@@ -34,9 +34,9 @@ export class WorkerServerProcess implements TsServerProcess {
 		]);
 	}
 
-	private _onDataHandlers = new Set<(data: Proto.Response) => void>();
-	private _onErrorHandlers = new Set<(err: Error) => void>();
-	private _onExitHandlers = new Set<(code: number | null, signal: string | null) => void>();
+	private readonly _onDataHandlers = new Set<(data: Proto.Response) => void>();
+	private readonly _onErrorHandlers = new Set<(err: Error) => void>();
+	private readonly _onExitHandlers = new Set<(code: number | null, signal: string | null) => void>();
 
 	public constructor(
 		private readonly worker: Worker,

extensions/typescript-language-features/src/typescriptServiceClient.ts

@@ -99,9 +99,9 @@ export default class TypeScriptServiceClient extends Disposable implements IType
 
 	private readonly workspaceState: vscode.Memento;
 
-	private _onReady?: { promise: Promise<void>; resolve: () => void; reject: () => void };
+	private readonly _onReady?: { promise: Promise<void>; resolve: () => void; reject: () => void };
 	private _configuration: TypeScriptServiceConfiguration;
-	private pluginPathsProvider: TypeScriptPluginPathsProvider;
+	private readonly pluginPathsProvider: TypeScriptPluginPathsProvider;
 	private readonly _versionManager: TypeScriptVersionManager;
 
 	private readonly logger = new Logger();

extensions/typescript-language-features/src/ui/jsNodeWalkthrough.electron.ts

@@ -50,7 +50,9 @@ export class CreateNewJSFileCommand {
 	public static readonly id = 'javascript-walkthrough.commands.createJsFile';
 	public readonly id = CreateNewJSFileCommand.id;
 
-	constructor(private walkthroughState: JsWalkthroughState) { }
+	constructor(
+		private readonly walkthroughState: JsWalkthroughState
+	) { }
 
 	public execute() {
 		createNewJSFile(this.walkthroughState);
@@ -61,7 +63,9 @@ export class DebugJsFileCommand {
 	public static readonly id = 'javascript-walkthrough.commands.debugJsFile';
 	public readonly id = DebugJsFileCommand.id;
 
-	constructor(private walkthroughState: JsWalkthroughState) { }
+	constructor(
+		private readonly walkthroughState: JsWalkthroughState
+	) { }
 
 	public execute() {
 		debugJsFile(this.walkthroughState);