Test migration to jest by hand

Apparently using regular expressions is way easier.

test/reducedFilter/reducedFilter.js

@@ -0,0 +1,8 @@
+const reducedFilter = (data, keys, fn) =>
+data.filter(fn).map(el =>
+keys.reduce((acc, key) => {
+acc[key] = el[key];
+return acc;
+}, {})
+);
+module.exports = reducedFilter;