Test migration to jest by hand

Apparently using regular expressions is way easier.

test/reduceSuccessive/reduceSuccessive.js

@@ -0,0 +1,3 @@
+const reduceSuccessive = (arr, fn, acc) =>
+arr.reduce((res, val, i, arr) => (res.push(fn(res.slice(-1)[0], val, i, arr)), res), [acc]);
+module.exports = reduceSuccessive;