Test migration to jest by hand

Apparently using regular expressions is way easier.

test/matchesWith/matchesWith.js

@@ -0,0 +1,8 @@
+const matchesWith = (obj, source, fn) =>
+Object.keys(source).every(
+key =>
+obj.hasOwnProperty(key) && fn
+? fn(obj[key], source[key], key, obj, source)
+: obj[key] == source[key]
+);
+module.exports = matchesWith;