Nesting a button inside a link

Introduction

If you have ever used Linear. You might notice that they use a link for their kanban item

But it’s also interactable

If you ever tried to build this, you might found some problem. That’s probably the reason you came across this article. It’s not entirely straightforward to nest an interactive button inside a link. How is that possible?

HTML5 Spec Disclaimer

Just for disclaimer, it’s actually not recommended to have a button nested inside an <a> tag.

The a element may be wrapped around entire paragraphs, lists, tables, and so forth, even entire sections, so long as there is no interactive content within (e.g. buttons or other links). - stackoverflow

I’m not well-versed on the a11y side of the web. But this link and nested interactive is getting more popular since linear used the same pattern.

If it has to be done

If your designer/PM said to ignore the spec and it has to be done. I got the solution.

I’m gonna walk you through the attempts that I made, and the flaws each step until I make the current working solution.

Note: My examples is going to use React. But it will be the same with any framework, because it’s purely DOM operations.

First Mundane Attempt

It’s quite natural to reach to this solution using markup

<a href='https://theodorusclarence.com'>
  hello this is a link
  <button onClick={open}>open combobox</button>
</a>

However, you’re gonna get quickly disappointed because when you have a button inside a link, the link default behavior will take precedence. Thus, clicking the button will send you directly to the link instead of doing the onClick.

Preventing Default

You can actually stop the <a> from redirecting by using e.preventDefault .

<a href='https://theodorusclarence.com' onClick={(e) => e.preventDefault()}>
  hello this is a link
  <button onClick={() => alert('open combobox')}>open combobox</button>
</a>

By preventing the default behavior, we won’t be redirected to the link.

That means, we can selectively prevent the default behavior when we are clicking a button.

<a
  href='https://theodorusclarence.com'
  onClick={(e) => {
    if (e.target instanceof HTMLElement && e.target.tagName === 'BUTTON') {
      e.preventDefault();
    }
  }}
>
  hello this is a link{' '}
  <button onClick={() => alert('open combobox')}>(open combobox)</button>
</a>

That works right? Or is it 🤨?

Putting icons inside a button

It’s very common for a button to have icons inside, or maybe other elements like span and stuff.

This is where another problem comes.

<a
  href='https://theodorusclarence.com'
  onClick={(e) => {
    if (e.target instanceof HTMLElement && e.target.tagName === 'BUTTON') {
      e.preventDefault();
    }
  }}
>
  hello this is a link{' '}
  <button onClick={() => alert('open combobox')}>
    <svg width='12' height='12' viewBox='0 0 12 12'>
      <circle cx='6' cy='6' r='6' fill='currentColor' />
    </svg>
  </button>
</a>

It doesn’t work.

If your button has svg inside, when we are checking the e.target.tagName it won’t detect as a button since we are actually clicking on the SVG element itself (circle)

Solution: Recursive Check

The solution is to do a recursive check up to the parent.

const checkIgnoreNestedLink = React.useCallback(
  (e: React.MouseEvent<HTMLAnchorElement>) => {
    let cur = e.target as HTMLElement;
 
    while (cur) {
      if (cur.dataset?.ignoreNestedLink) {
        return true;
      }
 
      if (cur.parentElement) {
        cur = cur.parentElement;
      } else {
        break;
      }
    }
 
    return false;
  },
  []
);
 
return (
  <button
    onClick={(e) => {
      if (checkIgnoreNestedLink(e)) {
        e.preventDefault();
      }
    }}
  >
    <svg />
  </button>
);

This code will ensure that we check all of the element that we click, as well as all of the parent elements until we found data-ignore-nested-link.

To use it, you can just add the data attribute to the button that you have.

<a>
  ...
  <button data-ignore-nested-link />
</a>

Note: If you’re using Radix UI, you also need to add the attribute to the popover content/other element content.

Conclusion

This will work since the check is guaranteed to be exhaustive. Good luck!