Test migration to jest by hand

Apparently using regular expressions is way easier.

test/rearg/rearg.js

@@ -0,0 +1,8 @@
+const rearg = (fn, indexes) => (...args) =>
+fn(
+...args.reduce(
+(acc, val, i) => ((acc[indexes.indexOf(i)] = val), acc),
+Array.from({ length: indexes.length })
+)
+);
+module.exports = rearg;