ran npm run tdd

test/flatten/flatten.js

@@ -1,4 +1,5 @@
-module.exports = flatten = (arr, depth = 1) =>
+const flatten = (arr, depth = 1) =>
 depth != 1
 ? arr.reduce((a, v) => a.concat(Array.isArray(v) ? flatten(v, depth - 1) : v), [])
-: arr.reduce((a, v) => a.concat(v), []);
+: arr.reduce((a, v) => a.concat(v), []);
+ module.exports = flatten