From 478471d8866d55b50adf995fac18356d5c16105a Mon Sep 17 00:00:00 2001
From: Auca Coyan <aucacoyan@gmail.com>
Date: Thu, 15 Jun 2023 08:52:14 -0300
Subject: [PATCH] :sparkles: add check if its missing a newline at EOF (#28)
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I resolved my git and did properly the #27 PR 😄
---
 src/formatting.rs | 12 ++++++++++--
 src/lib.rs        | 14 ++++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/src/formatting.rs b/src/formatting.rs
index 936864d..5b3d11e 100644
--- a/src/formatting.rs
+++ b/src/formatting.rs
@@ -137,8 +137,8 @@ pub fn format_inner(contents: &[u8], _config: &Config) -> Vec<u8> {
         // cleanup
         start = span.end + 1;
     }
-    // just before writing, append a new line to the file.
-    out = insert_newline(out);
+    // just before writing, check if a new line is needed.
+    out = add_newline_at_end_of_file(out);
 
     // timer = timer.done_formatting()
     out
@@ -156,6 +156,14 @@ fn insert_newline(mut bytes: Vec<u8>) -> Vec<u8> {
     bytes
 }
 
+/// Checks if it missing a new line. If true, adds it.
+fn add_newline_at_end_of_file(out: Vec<u8>) -> Vec<u8> {
+    match out.last() {
+        Some(&b'\n') => out,
+        _ => insert_newline(out),
+    }
+}
+
 /// Given a slice of bytes, strip all spaces, new lines and tabs found within
 ///
 /// Because you don't know how the incoming code is formatted,
diff --git a/src/lib.rs b/src/lib.rs
index 292f22f..ade417e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -120,6 +120,20 @@ myfunc(one)
         run_test(input, expected);
     }
 
+    #[test]
+    fn add_new_line() {
+        let input = "null";
+        let expected = "null\n";
+        run_test(input, expected);
+    }
+
+    #[test]
+    fn remove_additional_lines() {
+        let input = "let one = 1\n\n\n";
+        let expected = "let one = 1\n";
+        run_test(input, expected);
+    }
+
     #[test]
     fn remove_leading_whitespace() {
         let input = "   0";