How to add the "Copy" button to code blocks in Docusaurus

docusaurus-copy-button.md

Adding "Copy" (to Clipboard) Button

If you would like to add a button to your fenced code blocks so that users may copy the code, you can do so in Docusaurus. You will have to add some code to your Docusaurus project, as seen below.

Under static/js, create a file called code-block-buttons.js with the following:

// Turn off ESLint for this file because it's sent down to users as-is.
/* eslint-disable */
window.addEventListener('load', function() {
  function button(label, ariaLabel, icon, className) {
    const btn = document.createElement('button');
    btn.classList.add('btnIcon', className);
    btn.setAttribute('type', 'button');
    btn.setAttribute('aria-label', ariaLabel);
    btn.innerHTML =
      '<div class="btnIcon__body">' +
      icon +
      '<strong class="btnIcon__label">' +
      label +
      '</strong>' +
      '</div>';
    return btn;
  }

  function addButtons(codeBlockSelector, btn) {
    document.querySelectorAll(codeBlockSelector).forEach(function(code) {
      code.parentNode.appendChild(btn.cloneNode(true));
    });
  }

  const copyIcon =
    '<svg width="12" height="12" viewBox="340 364 14 15" xmlns="http://www.w3.org/2000/svg"><path fill="currentColor" d="M342 375.974h4v.998h-4v-.998zm5-5.987h-5v.998h5v-.998zm2 2.994v-1.995l-3 2.993 3 2.994v-1.996h5v-1.995h-5zm-4.5-.997H342v.998h2.5v-.997zm-2.5 2.993h2.5v-.998H342v.998zm9 .998h1v1.996c-.016.28-.11.514-.297.702-.187.187-.422.28-.703.296h-10c-.547 0-1-.452-1-.998v-10.976c0-.546.453-.998 1-.998h3c0-1.107.89-1.996 2-1.996 1.11 0 2 .89 2 1.996h3c.547 0 1 .452 1 .998v4.99h-1v-2.995h-10v8.98h10v-1.996zm-9-7.983h8c0-.544-.453-.996-1-.996h-1c-.547 0-1-.453-1-.998 0-.546-.453-.998-1-.998-.547 0-1 .452-1 .998 0 .545-.453.998-1 .998h-1c-.547 0-1 .452-1 .997z" fill-rule="evenodd"/></svg>';

  addButtons(
    '.hljs',
    button('Copy', 'Copy code to clipboard', copyIcon, 'btnClipboard'),
  );

  const clipboard = new ClipboardJS('.btnClipboard', {
    target: function(trigger) {
      return trigger.parentNode.querySelector('code');
    },
  });

  clipboard.on('success', function(event) {
    event.clearSelection();
    const textEl = event.trigger.querySelector('.btnIcon__label');
    textEl.textContent = 'Copied';
    setTimeout(function() {
      textEl.textContent = 'Copy';
    }, 2000);
  });
});

Under static/css, create a file called code-block-buttons.css and add the following:

/* "Copy" code block button */
pre {
  position: relative;
}

pre .btnIcon {
  position: absolute;
  top: 4px;
  z-index: 2;
  cursor: pointer;
  border: 1px solid transparent;
  padding: 0;
  color: #fff;
  background-color: transparent;
  height: 30px;
  transition: all .25s ease-out;
}

pre .btnIcon:hover {
  text-decoration: none;
}

.btnIcon__body {
  align-items: center;
  display: flex;
}

.btnIcon svg {
  fill: currentColor;
  margin-right: .4em;
}

.btnIcon__label {
  font-size: 11px;
}

.btnClipboard {
  right: 10px;
}

Add the following to siteConfig.js:

scripts: [
  'https://buttons.github.io/buttons.js',
  'https://cdnjs.cloudflare.com/ajax/libs/clipboard.js/2.0.0/clipboard.min.js',
  '/js/code-block-buttons.js',
],
stylesheets: ['/css/code-block-buttons.css']

Your "Copy" to clipboard buttons should now appear at the upper right of every fenced code block.

For anyone that's deploying to Github pages or using a baseUrl it won't work as is. The path of the JS script needs to be the same. So you need to do something like this...

// ...
baseUrl: '/your/base/url/'
  scripts: [
    'https://buttons.github.io/buttons.js',
    'https://cdnjs.cloudflare.com/ajax/libs/clipboard.js/2.0.0/clipboard.min.js',
    '/your/base/url/js/code-block-buttons.js',
  ],
// ...

It also breaks if you make the path with a template string. Hope this helps someone!

This should be in the main docs

Can this button be togglable on a per code block basis?

it seems that adding stylesheets actually doesnt work, you get a 404 trying to load the CSS. the CSS from that file, however, does end up included in the final generated main.css, so just removing stylesheets entry from the siteConfig.js would be the right thing to do here.

@reintroducing is right, adding stylesheets: ['/css/code-block-buttons.css'] is not needed, and in fact results in a 404.

Maybe someone should update the main docs instead of relying this outdated, standalone set of instructions.

Agreed. This should be part of the main docs.

Please upgrade to Docusaurus v2 instead! 😄

Can this button be togglable on a per code block basis?

This seems like a really good idea. Has anyone implemented it?

@steve-aerospike unless you're still using Docusaurus 1, this snippet is likely irrelevant.

That said, it probably can be done on a per code basis. You can add some flags or special code to your code blocks (implementation will be up to you) and customize the script to only add the copy button if the flag is not present.

Thanks for the reply. Yes, I see now where the CodeBlock section of the Docusaurus theme has a built-in copy/paste button, and I added a new arg to suppress it as requested for certain code blocks.

@steve-aerospike Hi. Did you do something like:

```js no-copy-button
let x=3;
```

Could you explain how you did it?

Yes, that's exactly it. I pulled out the CodeBlock/Content section from the @Docusaurus node module, and edited the file String.js. I added a noCopy arg to the CodeBlockString function definition, and edited the line which emits the copyButton to look for it.

Before editing:
<CopyButton className={styles.codeButton} code={code} />

After editing:
{!noCopy && <CopyButton className={styles.codeButton} code={code} />}

Thanks! I swizzled the CodeBlock/Content and used the metastring inside String.js to access the attributs in the markup file. I also added an edit button using this. See https://stackoverflow.com/questions/75409516/docusaurus-add-custom-button-to-code-block

Please note that swizzling is a Docusaurus 2 feature while this gist is only applicable to Docusaurus 1