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.

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