diff --git a/src/matchcode_toolkit/stemming.py b/src/matchcode_toolkit/stemming.py
index 11a7c4c..49282e1 100644
--- a/src/matchcode_toolkit/stemming.py
+++ b/src/matchcode_toolkit/stemming.py
@@ -149,7 +149,8 @@ def get_stem_code(location):
 
     # Apply mutations bottom-up
     mutations = dict(sorted(mutations.items(), reverse=True))
-    text = source.decode()
+    # Ensure the text always ends with a newline character.
+    text = source.decode().rstrip("\n") + "\n"
     cur_count = 0
     lines = text.splitlines(keepends=True)
     successive_line_count = [cur_count := cur_count + len(line) for line in lines]
diff --git a/tests/test_stemming.py b/tests/test_stemming.py
index cb37693..dd776e0 100644
--- a/tests/test_stemming.py
+++ b/tests/test_stemming.py
@@ -78,3 +78,9 @@ def test_rust_code_stemming(self):
         expected_file_location = self.test_data_dir / "rust/metrics-stemmeds.rs"
         results = stemming.get_stem_code(location=str(file_location))
         check_against_expected_code_file(results, expected_file_location)
+
+    def test_javascript_code_stemming_endwith_no_newline(self):
+        file_location = self.test_data_dir / "javascript/main.js"
+        expected_file_location = self.test_data_dir / "javascript/main-stemmed.js"
+        results = stemming.get_stem_code(location=str(file_location))
+        check_against_expected_code_file(results, expected_file_location)
diff --git a/tests/testfiles/stemming/javascript/main-stemmed.js b/tests/testfiles/stemming/javascript/main-stemmed.js
new file mode 100644
index 0000000..0b5742f
--- /dev/null
+++ b/tests/testfiles/stemming/javascript/main-stemmed.js
@@ -0,0 +1,2 @@
+const idf="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!@#$%^&*()_-+=";function idf(idf){let idf="";for(let idf=0;idf<idf;idf++){let idf=idf.floor(idf.random()*idf.length),idf=idf[idf];idf+=idf}return idf}const idf=idf(idf("Enter the desired length of your password:")),idf=idf(idf);idf(`Your random password is: ${idf}`);
+
diff --git a/tests/testfiles/stemming/javascript/main.js b/tests/testfiles/stemming/javascript/main.js
new file mode 100644
index 0000000..355446f
--- /dev/null
+++ b/tests/testfiles/stemming/javascript/main.js
@@ -0,0 +1,3 @@
+const charSet="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!@#$%^&*()_-+=";function generatePassword(r){let e="";for(let s=0;s<r;s++){let o=Math.floor(Math.random()*charSet.length),t=charSet[o];e+=t}return e}const passwordLength=parseInt(prompt("Enter the desired length of your password:")),password=generatePassword(passwordLength);alert(`Your random password is: ${password}`);
+
+/*# sourceMappingURL=main.js.map */
\ No newline at end of file