feat: add cache example of a decorator

Author: sensorario

typescript/decorators/cache/build/prova.js

@@ -0,0 +1,34 @@
+var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+    if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+    else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+    return c > 3 && r && Object.defineProperty(target, key, r), r;
+};
+function cache(target, key, descriptor) {
+    const originalMethod = descriptor.value;
+    const memory = new Map();
+    descriptor.value = function (...args) {
+        const key = JSON.stringify(args);
+        if (!memory.has(key)) {
+            console.log('calcolo valore');
+            const result = originalMethod.apply(this, args);
+            memory.set(key, result);
+            return result;
+        }
+        console.log('recupero valore');
+        return memory.get(key);
+    };
+    return descriptor;
+}
+class NonEAcqua {
+    doSomething(x) {
+        return x * 2;
+    }
+}
+__decorate([
+    cache
+], NonEAcqua.prototype, "doSomething", null);
+const obj = new NonEAcqua();
+obj.doSomething(42);
+obj.doSomething(42);
+obj.doSomething(42);

typescript/decorators/cache/package-lock.json

@@ -0,0 +1,5 @@
+{
+  "dependencies": {
+    "typescript": "^5.3.3"
+  }
+}

typescript/decorators/cache/package.json

@@ -0,0 +1,33 @@
+function cache(target: any, key: string, descriptor: PropertyDescriptor) {
+  const originalMethod = descriptor.value;
+  const memory = new Map<any, any>();
+
+  descriptor.value = function (...args: any[]) {
+    const key = JSON.stringify(args);
+
+    if (!memory.has(key)) {
+      console.log('calcolo valore')
+      const result = originalMethod.apply(this, args);
+      memory.set(key, result);
+      return result;
+    }
+
+    console.log('recupero valore')
+    return memory.get(key);
+  };
+
+  return descriptor;
+}
+
+class NonEAcqua {
+  @cache
+  doSomething(x: number): number {
+    return x * 2;
+  }
+}
+
+
+const obj = new NonEAcqua()
+obj.doSomething(42)
+obj.doSomething(42)
+obj.doSomething(42)

typescript/decorators/cache/prova.ts

@@ -0,0 +1,7 @@
+{
+  "compilerOptions": {
+    "target": "ES6",
+    "experimentalDecorators": true,
+    "outDir": "./build/"
+  }
+}