Merge pull request #1113 from ezracelli/master

[FIX] update implementation & explanation for mapObject

snippets/mapObject.md

@@ -1,20 +1,21 @@
 ---
 title: mapObject
-tags: array,object,advanced
+tags: array,object,intermediate
 ---
 
-Maps the values of an array to an object using a function, where the key-value pairs consist of the stringified value as the key and the mapped value.
+Maps the values of an array to an object using a function, where the key-value pairs consist of the original value as the key and the result of the function as the value.
 
-Use an anonymous inner function scope to declare an undefined memory space, using closures to store a return value. Use a new `Array` to store the array with a map of the function over its data set and a comma operator to return a second step, without needing to move from one context to another (due to closures and order of operations).
+Use `Array.prototype.reduce()` to apply `fn` to each element in `arr` and combine the results into an object.
+Use `el` as the key for each property and the result of `fn` as the value.
 
 ```js
-const mapObject = (arr, fn) =>
-  (a => (
-    (a = [arr, arr.map(fn)]), a[0].reduce((acc, val, ind) => ((acc[val] = a[1][ind]), acc), {})
-  ))();
+const mapObject = (arr, fn) => 
+  arr.reduce((acc, el, i) => {
+    acc[el] = fn(el, i, arr);
+    return acc;
+  }, {});
 ```
 
 ```js
-const squareIt = arr => mapObject(arr, a => a * a);
-squareIt([1, 2, 3]); // { 1: 1, 2: 4, 3: 9 }
-```
+mapObject([1, 2, 3], a => a * a); // { 1: 1, 2: 4, 3: 9 }
+```