From 09dee060b2c2c4a7757cb72a46a6422c34af8ce2 Mon Sep 17 00:00:00 2001
From: Andreas Lind <andreaslindpetersen@gmail.com>
Date: Tue, 17 Mar 2020 23:45:59 +0100
Subject: [PATCH] Fix: Newline before eof when creating config via --init
 (#12952)

* Fix: Newline before eof when creating config via --init

* Add test

* Make a dedicated test (with a bit of duplication)
---
 lib/init/config-file.js       |  4 ++--
 tests/lib/init/config-file.js | 15 +++++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/lib/init/config-file.js b/lib/init/config-file.js
index 960b572cddb3..fc62b81525e6 100644
--- a/lib/init/config-file.js
+++ b/lib/init/config-file.js
@@ -45,7 +45,7 @@ function sortByKey(a, b) {
 function writeJSONConfigFile(config, filePath) {
     debug(`Writing JSON config file: ${filePath}`);
 
-    const content = stringify(config, { cmp: sortByKey, space: 4 });
+    const content = `${stringify(config, { cmp: sortByKey, space: 4 })}\n`;
 
     fs.writeFileSync(filePath, content, "utf8");
 }
@@ -80,7 +80,7 @@ function writeJSConfigFile(config, filePath) {
     debug(`Writing JS config file: ${filePath}`);
 
     let contentToWrite;
-    const stringifiedContent = `module.exports = ${stringify(config, { cmp: sortByKey, space: 4 })};`;
+    const stringifiedContent = `module.exports = ${stringify(config, { cmp: sortByKey, space: 4 })};\n`;
 
     try {
         const { CLIEngine } = require("../cli-engine");
diff --git a/tests/lib/init/config-file.js b/tests/lib/init/config-file.js
index 45cca55f9336..69556b4b5b61 100644
--- a/tests/lib/init/config-file.js
+++ b/tests/lib/init/config-file.js
@@ -82,6 +82,21 @@ describe("ConfigFile", () => {
                 StubbedConfigFile.write(config, filename);
             });
 
+            it("should include a newline character at EOF", () => {
+                const fakeFS = leche.fake(fs);
+
+                sinon.mock(fakeFS).expects("writeFileSync").withExactArgs(
+                    filename,
+                    sinon.match(value => value.endsWith("\n")),
+                    "utf8"
+                );
+
+                const StubbedConfigFile = proxyquire("../../../lib/init/config-file", {
+                    fs: fakeFS
+                });
+
+                StubbedConfigFile.write(config, filename);
+            });
         });
 
         it("should make sure js config files match linting rules", () => {