Add reduce

Author: cristinafsanz

README.md

@@ -2,30 +2,12 @@
 
 Code snippets with gifs, to avoid copy and paste the code and write it all.
 
-## Files for each snippet
-
-There is a file for each functionality, to be able to execute it.
-
-Example:
-
-- File es6/forEach/forEach.js
-
-  - Make it executable: 
-  
-  ```
-  chmod +x es6/forEach/forEach.js
-  ```
-
-  - Run it:
-
-  ```
-  ./es6/forEach/forEach.js
-  ```
-
 ## Table of Contents
 
 - [forEach](#forEach)
 
+- [reduce](#reduce)
+
 ## forEach
 
 > Example:
@@ -41,3 +23,50 @@ array.forEach((item, index) => {
 > Gif:
 
 ![Escribir forEach paso a paso](es6/forEach/forEach.gif?raw=true)
+
+## reduce
+
+> Example:
+
+```javascript
+var pilots = [
+  {
+    id: 10,
+    name: "Poe Dameron",
+    years: 14,
+  },
+  {
+    id: 41,
+    name: "Tallissan Lintra",
+    years: 16,
+  },
+];
+
+const totalYears = pilots.reduce((acc, pilot) => acc + pilot.years, 0);
+```
+
+> Gif:
+
+![Escribir forEach paso a paso](es6/reduce/reduce.gif?raw=true)
+
+> [Useful use cases](https://itnext.io/useful-reduce-use-cases-91a86ee10bcd).
+
+## Files for each snippet
+
+There is a file for each functionality, to be able to execute it.
+
+Example:
+
+- File es6/forEach/forEach.js
+
+  - Make it executable: 
+  
+  ```
+  chmod +x es6/forEach/forEach.js
+  ```
+
+  - Run it:
+
+  ```
+  ./es6/forEach/forEach.js
+  ```

es6/reduce/reduce.gif

@@ -0,0 +1,20 @@
+#!/usr/bin/env node
+
+// From https://medium.com/poka-techblog/simplify-your-javascript-use-map-reduce-and-filter-bd02c593cc2d 
+
+var pilots = [
+  {
+    id: 10,
+    name: "Poe Dameron",
+    years: 14,
+  },
+  {
+    id: 41,
+    name: "Tallissan Lintra",
+    years: 16,
+  },
+];
+
+const totalYears = pilots.reduce((acc, pilot) => acc + pilot.years, 0);
+console.log({ totalYears });
+