Add WeakMap example

tshemsedinov · tshemsedinov · commit 928ae7f73516 · 2017-11-20T08:40:26.000+02:00
diff --git a/JavaScript/6-weak.js b/JavaScript/6-weak.js
@@ -0,0 +1,19 @@
+'use strict';
+
+const cities = {
+  beijing: { name: 'Beijing' },
+  kiev: { name: 'Kiev' },
+  london: { name: 'London' },
+  baghdad: { name: 'Baghdad' },
+};
+
+const capitalOf = new WeakMap();
+capitalOf.set(cities.beijing, 'People\'s Republic of China');
+capitalOf.set(cities.kiev, 'Ukraine');
+capitalOf.set(cities.london, 'United Kingdom');
+capitalOf.set(cities.baghdad, 'Iraq');
+
+delete cities.london;
+capitalOf.delete(cities.baghdad);
+
+console.dir({ cities, capitalOf });
