Add iterable example

tshemsedinov · tshemsedinov · commit 527b8be869ba · 2017-11-20T03:17:21.000+02:00
diff --git a/JavaScript/4-iterable.js b/JavaScript/4-iterable.js
@@ -0,0 +1,16 @@
+'use strict';
+
+const cityPopulation = new Map();
+
+cityPopulation.set('Shanghai', 24256800);
+cityPopulation.set('Beijing',  21516000);
+cityPopulation.set('Delhi',    16787941);
+cityPopulation.set('Lagos',    16060303);
+
+for (const city of cityPopulation) {
+  console.log(city);
+}
+
+for (const [name, population] of cityPopulation) {
+  console.log(`Population of ${name} is ${population}`);
+}
