problems(js): add “2635. Apply Transform Over Each Element in Array”

Signed-off-by: Matej Focko <mfocko@redhat.com>

problems/apply-transform-over-each-element-in-array.js

@@ -0,0 +1,15 @@
+/**
+ * @param {number[]} arr
+ * @param {Function} fn
+ * @return {number[]}
+ */
+var map = function(arr, fn) {
+    let mapped_arr = new Array();
+
+    let i = 0;
+    for (let x of arr) {
+        mapped_arr.push(fn(x, i++));
+    }
+
+    return mapped_arr;
+};