<pre class="language-javascript"><code class="language-javascript">
/**
 * @param {HTMLElement} el - element to be wrapped
 */
function $(el) {
 // your code here
 return new Wrapper(el);
}

class Wrapper {
 // create constructor for the class
 constructor(el){
 this.el = el;
 }
 css = (p,v) =&gt; {
 this.el.style[p] = v;
 // return this so that it's possible to chain further calls
 return this;
 }
}</code></pre>

Simple Solution with Comments

I believe you've used jQuery before, we often chain the jQuery methods together to accomplish our goals. For example, below chained call turns button …

16. create an Event Emitter

16. Event Emitterを作る

16. 实现一个Event Emitter

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

14. `memo()`を実装する

14. 实现`memo()`

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