How to detect when the div element width change (not window resize) in JS? -- [Question Asked]

const p = document.querySelector("p");
const button = document.querySelector("button");

const p$ = new MutationObserver((mutationList, observer) => {
  for (mutation of mutationList) {
    console.log(mutation);
  }
});

p$.observe(p, {
  attributes: true,
  childList: false,
  subtree: false
});

button.addEventListener("click", () => {
  p.style.width = "100px";
});

.wrapper {
  width: 400px;
}

.resizable {
  resize: both;
  overflow: scroll;
  border: 1px solid black;
}

<div class="wrapper">
  <p class="resizable">Hello</p>
  <button>Resize</button>
</div>

What is CSS?

Cascading Style Sheets, affectionately alluded to as CSS, is a basic plan language expected to work on the most common way of making website pages satisfactory.

CSS handles the look and feel a piece of a site page. Utilizing CSS, you have some control over the shade of the text, the style of text styles, the dispersing between passages, how segments are measured and spread out, what foundation pictures or tones are utilized, design designs,variations in show for various gadgets and screen sizes as well as different impacts.

CSS represents Cascading Style Sheets. It is a template language which is utilized to depict the look and organizing of a report written in markup language. It gives an extra component to HTML. It is for the most part utilized with HTML to change the style of website pages and UIs.

CSS is not difficult to learn and see however it gives strong command over the introduction of a HTML archive. Most normally, CSS is joined with the markup dialects HTML or XHTML.

Before CSS, labels like textual style, variety, foundation style, component arrangements, boundary and size must be rehashed on each website page. This was an extremely lengthy interaction. For instance: If you are fostering a huge site where textual styles and variety data are added on each and every page, it will be turned into a long and costly cycle. CSS was made to tackle this issue. It was a W3C suggestion.

CSS is utilized alongside HTML and JavaScript in many sites to make UIs for web applications and UIs for the majority versatile applications.