From 8531a230e5cef295c2cd7565d48178c41e4cd1cb Mon Sep 17 00:00:00 2001
From: Matt Bierner <matb@microsoft.com>
Date: Fri, 20 Jul 2018 17:58:43 -0700
Subject: [PATCH] Use flatten in a few places to improve readability

---
 extensions/typescript-language-features/src/extension.ts   | 6 +++++-
 .../typescript-language-features/src/features/task.ts      | 5 ++++-
 .../typescript-language-features/src/features/tsconfig.ts  | 7 +++++--
 .../typescript-language-features/src/utils/arrays.ts       | 4 ++++
 4 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/extensions/typescript-language-features/src/extension.ts b/extensions/typescript-language-features/src/extension.ts
index 2a6dd787d06..74f0ac6f509 100644
--- a/extensions/typescript-language-features/src/extension.ts
+++ b/extensions/typescript-language-features/src/extension.ts
@@ -16,6 +16,7 @@ import LogDirectoryProvider from './utils/logDirectoryProvider';
 import ManagedFileContextManager from './utils/managedFileContext';
 import { getContributedTypeScriptServerPlugins, TypeScriptServerPlugin } from './utils/plugins';
 import * as ProjectStatus from './utils/projectStatus';
+import { flatten } from './utils/arrays';
 
 
 export function activate(
@@ -36,7 +37,10 @@ export function activate(
 		context.subscriptions.push(module.register());
 	});
 
-	const supportedLanguage = [].concat.apply([], standardLanguageDescriptions.map(x => x.modeIds).concat(plugins.map(x => x.languages)));
+	const supportedLanguage = flatten([
+		...standardLanguageDescriptions.map(x => x.modeIds),
+		...plugins.map(x => x.languages)
+	]);
 	function didOpenTextDocument(textDocument: vscode.TextDocument): boolean {
 		if (isSupportedDocument(supportedLanguage, textDocument)) {
 			openListener.dispose();
diff --git a/extensions/typescript-language-features/src/features/task.ts b/extensions/typescript-language-features/src/features/task.ts
index 2dbacec79ec..e819a1c092b 100644
--- a/extensions/typescript-language-features/src/features/task.ts
+++ b/extensions/typescript-language-features/src/features/task.ts
@@ -78,7 +78,10 @@ class TscTaskProvider implements vscode.TaskProvider {
 
 	private async getAllTsConfigs(token: vscode.CancellationToken): Promise<TSConfig[]> {
 		const out = new Set<TSConfig>();
-		const configs = (await this.getTsConfigForActiveFile(token)).concat(await this.getTsConfigsInWorkspace());
+		const configs = [
+			...await this.getTsConfigForActiveFile(token),
+			...await this.getTsConfigsInWorkspace()
+		];
 		for (const config of configs) {
 			if (await exists(config.path)) {
 				out.add(config);
diff --git a/extensions/typescript-language-features/src/features/tsconfig.ts b/extensions/typescript-language-features/src/features/tsconfig.ts
index 25073d089f4..414c0f01148 100644
--- a/extensions/typescript-language-features/src/features/tsconfig.ts
+++ b/extensions/typescript-language-features/src/features/tsconfig.ts
@@ -6,6 +6,7 @@
 import * as jsonc from 'jsonc-parser';
 import { dirname, join } from 'path';
 import * as vscode from 'vscode';
+import { flatten } from '../utils/arrays';
 
 function mapNode<R>(node: jsonc.Node | undefined, f: (x: jsonc.Node) => R): R[] {
 	return node && node.type === 'array' && node.children
@@ -83,7 +84,9 @@ export function register() {
 
 	const languages = ['json', 'jsonc'];
 
-	const selector: vscode.DocumentSelector = ([] as any[]).concat(
-		...languages.map(language => patterns.map((pattern): vscode.DocumentFilter => ({ language, pattern }))));
+	const selector: vscode.DocumentSelector = flatten(
+		languages.map(language =>
+			patterns.map((pattern): vscode.DocumentFilter => ({ language, pattern }))));
+
 	return vscode.languages.registerDocumentLinkProvider(selector, new TsconfigLinkProvider());
 }
diff --git a/extensions/typescript-language-features/src/utils/arrays.ts b/extensions/typescript-language-features/src/utils/arrays.ts
index 57dbd54a29c..3a15e38981a 100644
--- a/extensions/typescript-language-features/src/utils/arrays.ts
+++ b/extensions/typescript-language-features/src/utils/arrays.ts
@@ -14,4 +14,8 @@ export function equals<T>(one: T[], other: T[], itemEquals: (a: T, b: T) => bool
 	}
 
 	return true;
+}
+
+export function flatten<T>(arr: T[][]): T[] {
+	return [].concat.apply([], arr);
 }
\ No newline at end of file