feat: add memoize function

src/js/util/DOM.js

@@ -1,4 +1,4 @@
-/* eslint-disable max-lines-per-function */
+import { memoize } from './index.js';
 
 export const $ = (() => {
   const constructor = function (selector) {
@@ -9,6 +9,10 @@ export const $ = (() => {
     this.target = this.targets.length === 1 && this.targets[0];
   };
 
+  const makeNewConstructor = function (selector) {
+    return new constructor(selector);
+  };
+
   constructor.prototype.each = function (callBack) {
     if (!callBack || typeof callBack !== 'function') {
       throw new Error('Custom DOM Library Error: this method needs callback function!');
@@ -129,8 +133,10 @@ export const $ = (() => {
     return this.target.checked;
   };
 
+  const memoized = memoize(makeNewConstructor);
+
   const instantiate = selector => {
-    return new constructor(selector);
+    return memoized(selector);
   };
 
   return instantiate;

src/js/util/index.js

@@ -1,3 +1,4 @@
 export { $ } from './DOM.js';
 export { validator } from './validator.js';
 export { getRandomNumber } from './getRandomNumber.js';
+export { memoize } from './memoize.js';

src/js/util/memoize.js

@@ -0,0 +1,11 @@
+export function memoize(callback) {
+  const cache = new Map();
+
+  return function (...args) {
+    if (!cache.get(args)) {
+      cache.set(args, new callback(args));
+    }
+
+    return cache.get(args);
+  };
+}