Create incomplete_alternativePattern.md

Author: mithunkumarc

mixins/incomplete_alternativePattern.md

@@ -0,0 +1,41 @@
+
+        // Each mixin is a traditional ES class
+        class Jumpable {
+          jump() {}
+        }
+
+        class Duckable {
+          duck() {}
+        }
+
+        // Including the base
+        class Sprite {
+          x = 0;
+          y = 0;
+        }
+
+        // Then you create an interface which merges
+        // the expected mixins with the same name as your base
+        interface Sprite extends Jumpable, Duckable {}
+        // Apply the mixins into the base class via
+        // the JS at runtime
+        applyMixins(Sprite, [Jumpable, Duckable]);
+
+        let player = new Sprite();
+        player.jump();
+        console.log(player.x, player.y);
+
+        // This can live anywhere in your codebase:
+        function applyMixins(derivedCtor: any, constructors: any[]) {
+          constructors.forEach((baseCtor) => {
+            Object.getOwnPropertyNames(baseCtor.prototype).forEach((name) => {
+              Object.defineProperty(
+                derivedCtor.prototype,
+                name,
+                Object.getOwnPropertyDescriptor(baseCtor.prototype, name)
+              );
+            });
+          });
+        }
+        
+This pattern relies less on the compiler, and more on your codebase to ensure both runtime and type-system are correctly kept in sync.