Test migration to jest by hand

Apparently using regular expressions is way easier.

test/isSorted/isSorted.js

@@ -0,0 +1,9 @@
+const isSorted = arr => {
+let direction = -(arr[0] - arr[1]);
+for (let [i, val] of arr.entries()) {
+direction = !direction ? -(arr[i - 1] - arr[i]) : direction;
+if (i === arr.length - 1) return !direction ? 0 : direction;
+else if ((val - arr[i + 1]) * direction > 0) return 0;
+}
+};
+module.exports = isSorted;