diff --git a/cli/diff.rs b/cli/diff.rs
index 1adb3da4aa..33af8bf0eb 100644
--- a/cli/diff.rs
+++ b/cli/diff.rs
@@ -3,6 +3,142 @@
 use crate::colors;
 use dissimilar::{diff as difference, Chunk};
 
+/// Print diff of the same file_path, before and after formatting.
+///
+/// Diff format is loosely based on Github diff formatting.
+pub fn diff(orig_text: &str, edit_text: &str) -> String {
+  if orig_text == edit_text {
+    return String::new();
+  }
+
+  // normalize newlines as it adds too much noise if they differ
+  let orig_text = orig_text.replace("\r\n", "\n");
+  let edit_text = edit_text.replace("\r\n", "\n");
+
+  if orig_text == edit_text {
+    return " | Text differed by line endings.\n".to_string();
+  }
+
+  DiffBuilder::build(&orig_text, &edit_text)
+}
+
+struct DiffBuilder {
+  output: String,
+  line_number_width: usize,
+  orig_line: usize,
+  edit_line: usize,
+  orig: String,
+  edit: String,
+  has_changes: bool,
+}
+
+impl DiffBuilder {
+  pub fn build(orig_text: &str, edit_text: &str) -> String {
+    let mut diff_builder = DiffBuilder {
+      output: String::new(),
+      orig_line: 1,
+      edit_line: 1,
+      orig: String::new(),
+      edit: String::new(),
+      has_changes: false,
+      line_number_width: {
+        let line_count = std::cmp::max(
+          orig_text.split('\n').count(),
+          edit_text.split('\n').count(),
+        );
+        line_count.to_string().chars().count()
+      },
+    };
+
+    let chunks = difference(orig_text, edit_text);
+    diff_builder.handle_chunks(chunks);
+    diff_builder.output
+  }
+
+  fn handle_chunks<'a>(&'a mut self, chunks: Vec<Chunk<'a>>) {
+    for chunk in chunks {
+      match chunk {
+        Chunk::Delete(s) => {
+          let split = s.split('\n').enumerate();
+          for (i, s) in split {
+            if i > 0 {
+              self.orig.push('\n');
+            }
+            self.orig.push_str(&fmt_rem_text_highlight(s));
+          }
+          self.has_changes = true
+        }
+        Chunk::Insert(s) => {
+          let split = s.split('\n').enumerate();
+          for (i, s) in split {
+            if i > 0 {
+              self.edit.push('\n');
+            }
+            self.edit.push_str(&fmt_add_text_highlight(s));
+          }
+          self.has_changes = true
+        }
+        Chunk::Equal(s) => {
+          let split = s.split('\n').enumerate();
+          for (i, s) in split {
+            if i > 0 {
+              self.flush_changes();
+            }
+            self.orig.push_str(&fmt_rem_text(s));
+            self.edit.push_str(&fmt_add_text(s));
+          }
+        }
+      }
+    }
+
+    self.flush_changes();
+  }
+
+  fn flush_changes(&mut self) {
+    if self.has_changes {
+      self.write_line_diff();
+
+      self.orig_line += self.orig.split('\n').count();
+      self.edit_line += self.edit.split('\n').count();
+      self.has_changes = false;
+    } else {
+      self.orig_line += 1;
+      self.edit_line += 1;
+    }
+
+    self.orig.clear();
+    self.edit.clear();
+  }
+
+  fn write_line_diff(&mut self) {
+    let split = self.orig.split('\n').enumerate();
+    for (i, s) in split {
+      self.output.push_str(&format!(
+        "{:width$}{} ",
+        self.orig_line + i,
+        colors::gray(" |"),
+        width = self.line_number_width
+      ));
+      self.output.push_str(&fmt_rem());
+      self.output.push_str(s);
+      self.output.push('\n');
+    }
+
+    let split = self.edit.split('\n').enumerate();
+    for (i, s) in split {
+      self.output.push_str(&format!(
+        "{:width$}{} ",
+        self.edit_line + i,
+        colors::gray(" |"),
+        width = self.line_number_width
+      ));
+      self.output.push_str(&fmt_add());
+      self.output.push_str(s);
+      self.output.push('\n');
+    }
+  }
+}
+
 fn fmt_add() -> String {
   colors::green_bold("+").to_string()
 }
@@ -27,146 +163,60 @@ fn fmt_rem_text_highlight(x: &str) -> String {
   colors::white_on_red(x).to_string()
 }
 
-fn write_line_diff(
-  diff: &mut String,
-  orig_line: &mut usize,
-  edit_line: &mut usize,
-  line_number_width: usize,
-  orig: &mut String,
-  edit: &mut String,
-) {
-  let split = orig.split('\n').enumerate();
-  for (i, s) in split {
-    diff.push_str(&format!(
-      "{:width$}{} ",
-      *orig_line + i,
-      colors::gray(" |"),
-      width = line_number_width
-    ));
-    diff.push_str(&fmt_rem());
-    diff.push_str(s);
-    diff.push('\n');
-  }
-
-  let split = edit.split('\n').enumerate();
-  for (i, s) in split {
-    diff.push_str(&format!(
-      "{:width$}{} ",
-      *edit_line + i,
-      colors::gray(" |"),
-      width = line_number_width
-    ));
-    diff.push_str(&fmt_add());
-    diff.push_str(s);
-    diff.push('\n');
-  }
-
-  *orig_line += orig.split('\n').count();
-  *edit_line += edit.split('\n').count();
-
-  orig.clear();
-  edit.clear();
-}
-
-/// Print diff of the same file_path, before and after formatting.
-///
-/// Diff format is loosely based on Github diff formatting.
-pub fn diff(orig_text: &str, edit_text: &str) -> String {
-  let lines = edit_text.split('\n').count();
-  let line_number_width = lines.to_string().chars().count();
-
-  let mut diff = String::new();
-
-  let mut text1 = orig_text.to_string();
-  let mut text2 = edit_text.to_string();
-
-  if !text1.ends_with('\n') {
-    text1.push('\n');
-  }
-  if !text2.ends_with('\n') {
-    text2.push('\n');
-  }
-
-  let mut orig_line: usize = 1;
-  let mut edit_line: usize = 1;
-  let mut orig: String = String::new();
-  let mut edit: String = String::new();
-  let mut changes = false;
-
-  let chunks = difference(&text1, &text2);
-  for chunk in chunks {
-    match chunk {
-      Chunk::Delete(s) => {
-        let split = s.split('\n').enumerate();
-        for (i, s) in split {
-          if i > 0 {
-            orig.push('\n');
-          }
-          orig.push_str(&fmt_rem_text_highlight(s));
-        }
-        changes = true
-      }
-      Chunk::Insert(s) => {
-        let split = s.split('\n').enumerate();
-        for (i, s) in split {
-          if i > 0 {
-            edit.push('\n');
-          }
-          edit.push_str(&fmt_add_text_highlight(s));
-        }
-        changes = true
-      }
-      Chunk::Equal(s) => {
-        let split = s.split('\n').enumerate();
-        for (i, s) in split {
-          if i > 0 {
-            if changes {
-              write_line_diff(
-                &mut diff,
-                &mut orig_line,
-                &mut edit_line,
-                line_number_width,
-                &mut orig,
-                &mut edit,
-              );
-              changes = false
-            } else {
-              orig.clear();
-              edit.clear();
-              orig_line += 1;
-              edit_line += 1;
-            }
-          }
-          orig.push_str(&fmt_rem_text(s));
-          edit.push_str(&fmt_add_text(s));
-        }
-      }
-    }
-  }
-  diff
-}
-
 #[cfg(test)]
 mod tests {
   use super::*;
 
   #[test]
   fn test_diff() {
-    let simple_console_log_unfmt = "console.log('Hello World')";
-    let simple_console_log_fmt = "console.log(\"Hello World\");";
-    assert_eq!(
-      colors::strip_ansi_codes(&diff(
-        simple_console_log_unfmt,
-        simple_console_log_fmt
-      )),
-      "1 | -console.log('Hello World')\n1 | +console.log(\"Hello World\");\n"
+    run_test(
+      "console.log('Hello World')",
+      "console.log(\"Hello World\");",
+      concat!(
+        "1 | -console.log('Hello World')\n",
+        "1 | +console.log(\"Hello World\");\n",
+      ),
     );
 
-    let line_number_unfmt = "\n\n\n\nconsole.log(\n'Hello World'\n)";
-    let line_number_fmt = "console.log(\n\"Hello World\"\n);";
+    run_test(
+      "\n\n\n\nconsole.log(\n'Hello World'\n)",
+      "console.log(\n\"Hello World\"\n);",
+      concat!(
+        "1 | -\n",
+        "2 | -\n",
+        "3 | -\n",
+        "4 | -\n",
+        "5 | -console.log(\n",
+        "1 | +console.log(\n",
+        "6 | -'Hello World'\n",
+        "2 | +\"Hello World\"\n",
+        "7 | -)\n3 | +);\n",
+      ),
+    );
+  }
+
+  #[test]
+  fn test_eof_newline_missing() {
+    run_test(
+      "test\nsome line text test",
+      "test\nsome line text test\n",
+      concat!(
+        "2 | -some line text test\n",
+        "2 | +some line text test\n",
+        "3 | +\n",
+      ),
+    );
+  }
+
+  #[test]
+  fn test_newlines_differing() {
+    run_test("test\n", "test\r\n", " | Text differed by line endings.\n");
+  }
+
+  fn run_test(diff_text1: &str, diff_text2: &str, expected_output: &str) {
     assert_eq!(
-      colors::strip_ansi_codes(&diff(line_number_unfmt, line_number_fmt)),
-      "1 | -\n2 | -\n3 | -\n4 | -\n5 | -console.log(\n1 | +console.log(\n6 | -'Hello World'\n2 | +\"Hello World\"\n7 | -)\n3 | +);\n"
+      colors::strip_ansi_codes(&diff(diff_text1, diff_text2,)),
+      expected_output,
     );
   }
 }