generate new test that did already exist & update all module snippets with declaration

test/partition/partition.js

@@ -1,4 +1,4 @@
-module.exports = (arr, fn) =>
+module.exports = partition = (arr, fn) =>
 arr.reduce(
 (acc, val, i, arr) => {
 acc[fn(val, i, arr) ? 0 : 1].push(val);