update pick.md -> oneline & simpler solution

snippets/pick.md

@@ -1,18 +1,9 @@
 ### Pick
 
-Use `Objexts.keys()` to convert given object to an iterable arr of keys.
-Use `.filter()` to filter the given arr of keys to the expected arr of picked keys.
-Use `.reduce()` to convert the filtered/picked keys back to a object with the corresponding key:value pair.
+Use `.reduce()` to convert the filtered/picked keys back to a object with the corresponding key:value pair if the key exist in the obj.
 
 ```js
-const pick = (obj, arr) =>
-  Object
-    .keys(obj)
-    .filter((v, i) => arr.indexOf(v) !== -1 )
-    .reduce((acc, cur, i) => {
-      acc[cur] = obj[cur];
-      return acc;
-    }, {});
+const pick = (obj, arr) => arr.reduce((acc, curr) => (curr in obj && (acc[curr] = obj[curr]), acc), {});
 
 // const object = { 'a': 1, 'b': '2', 'c': 3 };
 // pick(object, ['a', 'c']) -> { 'a': 1, 'c': 3 }