Merge pull request #885 from iaptsiauri/deepMapKeys

[FEATURE] adds deepMapKeys snippet

snippets/deepMapKeys.md

@@ -0,0 +1,54 @@
+### deepMapKeys
+
+Deep maps an object 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(obj)` 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, f) => (
+  Array.isArray(obj)
+    ? obj.map(val => deepMapKeys(val, f))
+    : (typeof obj === 'object')
+    ? Object.keys(obj).reduce((acc, current) => {
+      const val = obj[current];
+      acc[f(current)] = (val !== null && typeof val === 'object')
+        ? deepMapKeys(val, f)
+        : acc[f(current)] = 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' ]
+        }
+      ]
+    }
+  }
+}
+*/
+```

tag_database

@@ -50,6 +50,7 @@ decapitalize:string,array,intermediate
 deepClone:object,recursion,intermediate
 deepFlatten:array,recursion,intermediate
 deepFreeze:object,recursion,intermediate
+deepMapKeys:object,recursion,advanced
 defaults:object,intermediate
 defer:function,intermediate
 degreesToRads:math,beginner

test/deepMapKeys.test.js

@@ -0,0 +1,32 @@
+const expect = require('expect');
+const { deepMapKeys, toCamelCase } = require('./_30s.js');
+
+test('deepMapKeys is a Function', () => {
+  expect(deepMapKeys).toBeInstanceOf(Function);
+});
+
+test('Deep maps object keys', () => {
+  const obj = {
+    'foo_bar': 'hello',
+    'deep_child': {
+      'child_array': ['hello'],
+      'child_object_array': [
+        { 'hola_hello': 'Gamarjoba' }
+      ]
+    }
+  };
+  const expected = {
+    fooBar: 'hello',
+    deepChild: {
+      childArray: ['hello'],
+      childObjectArray: [
+        {
+          holaHello: 'Gamarjoba'
+        }
+      ]
+    }
+  };
+  const camleCaseKeys = k => toCamelCase(k);
+  expect(deepMapKeys(obj, camleCaseKeys)).toEqual(expected);
+});
+