<pre class="language-javascript"><code class="language-javascript">/**
 * @param {Function} func
 * @param {(args:[]) =&gt; string } [resolver] - cache key generator
 */
function memo(func, resolver) {
 let funcMap = new Map();
 return function(...args) { // use rest operator as it converts parameter to array and join can be applied only on arrays 
 let mapKey = resolver ? resolver(...args) : args.join('_')
 let isCached = funcMap.has(mapKey)
 if(isCached) {
 return funcMap.get(mapKey)
 }
 // let res = func.call(this,...args) //use spread operator since its call
 let res = func.apply(this,args)
 funcMap.set(mapKey, res)
 return res
 }
}
</code></pre>

Simple solution with explanation

Memoization is a common technique to boost performance. If you use React, you definitely have used React.memo before. Memoization is also commonly use…

15. implement a simple DOM wrapper to support method chaining like jQuery

15. jQueryみたいなDOM wrapperを実装する

15. 实现类似jQuery的DOM wrapper

13. Implement a Queue by using Stack

13. Stackを使ってQueueを作る

13. 利用栈(Stack)创建队列(Queue)

14. Implement a general memoization function - `memo()`

14. `memo()`を実装する

14. 实现`memo()`