Use undefined instead of null

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

@@ -158,7 +158,7 @@ class TscTaskProvider implements vscode.TaskProvider {
 		return undefined;
 	}
 
-	private getActiveTypeScriptFile(): string | null {
+	private getActiveTypeScriptFile(): string | undefined {
 		const editor = vscode.window.activeTextEditor;
 		if (editor) {
 			const document = editor.document;
@@ -166,7 +166,7 @@ class TscTaskProvider implements vscode.TaskProvider {
 				return this.client.value.toPath(document.uri);
 			}
 		}
-		return null;
+		return undefined;
 	}
 
 	private async getTasksForProject(project: TSConfig): Promise<vscode.Task[]> {

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

@@ -63,14 +63,14 @@ export interface ITypeScriptServiceClient {
 	 *
 	 * Does not try handling case insensitivity.
 	 */
-	normalizedPath(resource: vscode.Uri): string | null;
+	normalizedPath(resource: vscode.Uri): string | undefined;
 
 	/**
 	 * Map a resource to a normalized path
 	 *
 	 * This will attempt to handle case insensitivity.
 	 */
-	toPath(resource: vscode.Uri): string | null;
+	toPath(resource: vscode.Uri): string | undefined;
 
 	/**
 	 * Convert a path to a resource.

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

@@ -488,7 +488,7 @@ export default class TypeScriptServiceClient extends Disposable implements IType
 		}
 	}
 
-	public normalizedPath(resource: vscode.Uri): string | null {
+	public normalizedPath(resource: vscode.Uri): string | undefined {
 		if (this._apiVersion.gte(API.v213)) {
 			if (resource.scheme === fileSchemes.walkThroughSnippet || resource.scheme === fileSchemes.untitled) {
 				const dirName = path.dirname(resource.path);
@@ -498,19 +498,19 @@ export default class TypeScriptServiceClient extends Disposable implements IType
 		}
 
 		if (resource.scheme !== fileSchemes.file) {
-			return null;
+			return undefined;
 		}
 
 		const result = resource.fsPath;
 		if (!result) {
-			return null;
+			return undefined;
 		}
 
 		// Both \ and / must be escaped in regular expressions
 		return result.replace(new RegExp('\\' + this.pathSeparator, 'g'), '/');
 	}
 
-	public toPath(resource: vscode.Uri): string | null {
+	public toPath(resource: vscode.Uri): string | undefined {
 		return this.normalizedPath(resource);
 	}
 

extensions/typescript-language-features/src/utils/managedFileContext.ts

@@ -17,7 +17,7 @@ export default class ManagedFileContextManager {
 	private readonly onDidChangeActiveTextEditorSub: vscode.Disposable;
 
 	public constructor(
-		private readonly normalizePath: (resource: vscode.Uri) => string | null
+		private readonly normalizePath: (resource: vscode.Uri) => string | undefined
 	) {
 		this.onDidChangeActiveTextEditorSub = vscode.window.onDidChangeActiveTextEditor(this.onDidChangeActiveTextEditor, this);
 

extensions/typescript-language-features/src/utils/resourceMap.ts

@@ -18,7 +18,7 @@ export class ResourceMap<T> {
 	private readonly _map = new Map<string, { resource: vscode.Uri, value: T }>();
 
 	constructor(
-		private readonly _normalizePath: (resource: vscode.Uri) => string | null = (resource) => resource.fsPath
+		private readonly _normalizePath: (resource: vscode.Uri) => string | undefined = (resource) => resource.fsPath
 	) { }
 
 	public get size() {
@@ -71,7 +71,7 @@ export class ResourceMap<T> {
 		return this._map.values();
 	}
 
-	private toKey(resource: vscode.Uri): string | null {
+	private toKey(resource: vscode.Uri): string | undefined {
 		const key = this._normalizePath(resource);
 		if (!key) {
 			return key;

extensions/typescript-language-features/src/utils/versionStatus.ts

@@ -12,7 +12,7 @@ export default class VersionStatus {
 	private readonly _versionBarEntry: vscode.StatusBarItem;
 
 	constructor(
-		private readonly _normalizePath: (resource: vscode.Uri) => string | null
+		private readonly _normalizePath: (resource: vscode.Uri) => string | undefined
 	) {
 		this._versionBarEntry = vscode.window.createStatusBarItem(vscode.StatusBarAlignment.Right, 99 /* to the right of editor status (100) */);
 		this._onChangeEditorSub = vscode.window.onDidChangeActiveTextEditor(this.showHideStatus, this);