feat: add tutorial of proxy

Author: MikhailMasny

index.html

@@ -17,6 +17,7 @@
     <!-- <script src="src/promise.js"></script> -->
     <!-- <script src="src/object.js"></script> -->
     <!-- <script src="src/class.js"></script> -->
-    <script src="src/async-await.js"></script>
+    <!-- <script src="src/async-await.js"></script> -->
+    <!-- <script src="src/proxy.js"></script> -->
 </body>
 </html>

src/proxy.js

@@ -0,0 +1,67 @@
+// This is simple object.
+const someObject = {
+    prop1: "Property One",
+    prop2: 1
+}
+
+// This is proxy object.
+const objectProxy = new Proxy(someObject, {
+    get (target, prop) {
+        console.log(`Target is ${target}`);
+        console.log(`Prop is ${prop}`);
+        return target[prop];
+    },
+    set (target, prop, value) {
+        if (prop in target) {
+            target[prop] = value;
+        } else {
+            throw new Error("Bad prop.");
+        }
+    },
+    has (target, prop) {
+        return ["prop1", "prop2"].includes(prop);
+    },
+    deleteProperty(target, prop) {
+        delete target[prop];
+        return true;
+    }
+});
+
+// This is simple function.
+// const someFunc = text => console.log(text);
+const someFunc = function(text) {
+    console.log(text);
+}
+
+// This is proxy function.
+const funcProxy = new Proxy(someFunc, {
+    apply(target, thisArg, args) {
+        console.log(`Target is: ${target}`);
+        console.log(`This arg is: ${thisArg}`);
+        console.log(`Args is: ${args}`);
+
+        return target.apply(thisArg, args).toUpperCase();
+    }
+});
+
+// This is simple class.
+class SomeClass {
+    constructor(prop1, prop2) {
+        this.prop1 = prop1;
+        this.prop2 = prop2;
+    }
+}
+
+// This is proxy class.
+const ClassProxy = new Proxy(SomeClass, {
+    construct(target, args) {
+        return new Proxy(new target(...args), {
+            get (t, prop) {
+                console.log(prop);
+                return t[prop];
+            }
+        })
+    }
+});
+
+const proxy = new ClassProxy("Some property", 123);