extensions/typescript-language-features/src/task/taskProvider.ts/TscTaskProvider/getActiveTypeScriptFile
class TscTaskProvider:	private getActiveTypeScriptFile(): string | undefined {
		const editor = vscode.window.activeTextEditor;
		if (editor) {
			const document = editor.document;
			if (document && (document.languageId === 'typescript' || document.languageId === 'typescriptreact')) {
				return this.client.value.toPath(document.uri);
			}
		}
		return undefined;
	}