Nest all content into snippets

snippets/js/s/map-keys.md

@@ -0,0 +1,25 @@
+---
+title: Map object keys
+type: snippet
+language: javascript
+tags: [object]
+cover: rocky-mountains-2
+dateModified: 2020-10-21T21:54:53+03:00
+---
+
+Maps the keys of an object using the provided function, generating a new object.
+
+- Use `Object.keys()` to iterate over the object's keys.
+- Use `Array.prototype.reduce()` to create a new object with the same values and mapped keys using `fn`.
+
+```js
+const mapKeys = (obj, fn) =>
+  Object.keys(obj).reduce((acc, k) => {
+    acc[fn(obj[k], k, obj)] = obj[k];
+    return acc;
+  }, {});
+```
+
+```js
+mapKeys({ a: 1, b: 2 }, (val, key) => key + val); // { a1: 1, b2: 2 }
+```