1 files changed, 66 insertions, 0 deletions
diff --git a/app/assets/javascripts/behaviors/copy_code.js b/app/assets/javascripts/behaviors/copy_code.js
new file mode 100644
index 00000000000..a6e203ea5a2
--- /dev/null
+++ b/app/assets/javascripts/behaviors/copy_code.js
@@ -0,0 +1,66 @@
+import { uniqueId } from 'lodash';
+import { __ } from '~/locale';
+import { spriteIcon } from '~/lib/utils/common_utils';
+import { setAttributes } from '~/lib/utils/dom_utils';
+
+class CopyCodeButton extends HTMLElement {
+  connectedCallback() {
+    this.for = uniqueId('code-');
+
+    this.parentNode.querySelector('pre').setAttribute('id', this.for);
+
+    this.appendChild(this.createButton());
+  }
+
+  createButton() {
+    const button = document.createElement('button');
+
+    setAttributes(button, {
+      type: 'button',
+      class: 'btn btn-default btn-md gl-button btn-icon has-tooltip',
+      'data-title': __('Copy to clipboard'),
+      'data-clipboard-target': `pre#${this.for}`,
+    });
+
+    button.innerHTML = spriteIcon('copy-to-clipboard');
+
+    return button;
+  }
+}
+
+function addCodeButton() {
+  [...document.querySelectorAll('pre.code.js-syntax-highlight')]
+    .filter((el) => !el.closest('.js-markdown-code'))
+    .forEach((el) => {
+      const copyCodeEl = document.createElement('copy-code');
+      copyCodeEl.setAttribute('for', uniqueId('code-'));
+
+      const wrapper = document.createElement('div');
+      wrapper.className = 'gl-relative markdown-code-block js-markdown-code';
+      wrapper.appendChild(el.cloneNode(true));
+      wrapper.appendChild(copyCodeEl);
+
+      el.parentNode.insertBefore(wrapper, el);
+
+      el.remove();
+    });
+}
+
+export const initCopyCodeButton = (selector = '#content-body') => {
+  if (!customElements.get('copy-code')) {
+    customElements.define('copy-code', CopyCodeButton);
+  }
+
+  const el = document.querySelector(selector);
+
+  if (!el) return () => {};
+
+  const observer = new MutationObserver(() => addCodeButton());
+
+  observer.observe(document.querySelector(selector), {
+    childList: true,
+    subtree: true,
+  });
+
+  return () => observer.disconnect();
+};