Rename js snippets

snippets/js/s/deep-map-object-keys.md

@@ -0,0 +1,59 @@
+---
+title: Deep map object keys
+type: snippet
+language: javascript
+tags: [object,recursion]
+cover: duck-plants
+dateModified: 2020-09-15T16:28:04+03:00
+---
+
+Deep maps an object's keys.
+
+- Creates an object with the same values as the provided object and keys generated by running the provided function for each key.
+- 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 deepMapKeys = (obj, fn) =>
+  Array.isArray(obj)
+    ? obj.map(val => deepMapKeys(val, fn))
+    : typeof obj === 'object'
+    ? Object.keys(obj).reduce((acc, current) => {
+        const key = fn(current);
+        const val = obj[current];
+        acc[key] =
+          val !== null && typeof val === 'object' ? deepMapKeys(val, fn) : val;
+        return acc;
+      }, {})
+    : obj;
+```
+
+```js
+const obj = {
+  foo: '1',
+  nested: {
+    child: {
+      withArray: [
+        {
+          grandChild: ['hello']
+        }
+      ]
+    }
+  }
+};
+const upperKeysObj = deepMapKeys(obj, key => key.toUpperCase());
+/*
+{
+  "FOO":"1",
+  "NESTED":{
+    "CHILD":{
+      "WITHARRAY":[
+        {
+          "GRANDCHILD":[ 'hello' ]
+        }
+      ]
+    }
+  }
+}
+*/
+```