Test migration to jest by hand

Apparently using regular expressions is way easier.

test/partition/partition.js

@@ -0,0 +1,9 @@
+const partition = (arr, fn) =>
+arr.reduce(
+(acc, val, i, arr) => {
+acc[fn(val, i, arr) ? 0 : 1].push(val);
+return acc;
+},
+[[], []]
+);
+module.exports = partition;