diff --git a/src/node-to-fsa/__tests__/util.test.ts b/src/node-to-fsa/__tests__/util.test.ts
new file mode 100644
index 000000000..c9775e912
--- /dev/null
+++ b/src/node-to-fsa/__tests__/util.test.ts
@@ -0,0 +1,27 @@
+import {basename} from '../util';
+
+describe('basename()', () => {
+  test('handles empty string', () => {
+    expect(basename('')).toBe('');
+  });
+
+  test('return the same string if there is no nesting', () => {
+    expect(basename('scary.exe')).toBe('scary.exe');
+  });
+
+  test('returns last step in path', () => {
+    expect(basename('/gg/wp/hf/gl.txt')).toBe('gl.txt');
+    expect(basename('gg/wp/hf/gl.txt')).toBe('gl.txt');
+    expect(basename('/wp/hf/gl.txt')).toBe('gl.txt');
+    expect(basename('wp/hf/gl.txt')).toBe('gl.txt');
+    expect(basename('/hf/gl.txt')).toBe('gl.txt');
+    expect(basename('hf/gl.txt')).toBe('gl.txt');
+    expect(basename('/gl.txt')).toBe('gl.txt');
+    expect(basename('gl.txt')).toBe('gl.txt');
+  });
+
+  test('handles double slashes', () => {
+    expect(basename('/gg/wp/hf//gl.txt')).toBe('gl.txt');
+    expect(basename('//gl.txt')).toBe('gl.txt');
+  });
+});
diff --git a/src/node-to-fsa/util.ts b/src/node-to-fsa/util.ts
new file mode 100644
index 000000000..676d3d24b
--- /dev/null
+++ b/src/node-to-fsa/util.ts
@@ -0,0 +1,4 @@
+export const basename = (path: string) => {
+  const lastSlashIndex = path.lastIndexOf('/');
+  return lastSlashIndex === -1 ? path : path.slice(lastSlashIndex + 1);
+};