1 files changed, 73 insertions, 0 deletions

diff --git a/app/assets/javascripts/behaviors/copy_to_clipboard.js b/app/assets/javascripts/behaviors/copy_to_clipboard.js
new file mode 100644
index 00000000000..b669b63d23c
--- /dev/null
+++ b/app/assets/javascripts/behaviors/copy_to_clipboard.js
@@ -0,0 +1,73 @@
+import Clipboard from 'clipboard';
+
+function showTooltip(target, title) {
+  const $target = $(target);
+  const originalTitle = $target.data('originalTitle');
+
+  if (!$target.data('hideTooltip')) {
+    $target
+      .attr('title', title)
+      .tooltip('fixTitle')
+      .tooltip('show')
+      .attr('title', originalTitle)
+      .tooltip('fixTitle');
+  }
+}
+
+function genericSuccess(e) {
+  showTooltip(e.trigger, 'Copied');
+  // Clear the selection and blur the trigger so it loses its border
+  e.clearSelection();
+  $(e.trigger).blur();
+}
+
+/**
+ * Safari > 10 doesn't support `execCommand`, so instead we inform the user to copy manually.
+ * See http://clipboardjs.com/#browser-support
+ */
+function genericError(e) {
+  let key;
+  if (/Mac/i.test(navigator.userAgent)) {
+    key = '⌘'; // Command
+  } else {
+    key = 'Ctrl';
+  }
+  showTooltip(e.trigger, `Press ${key}-C to copy`);
+}
+
+export default function initCopyToClipboard() {
+  const clipboard = new Clipboard('[data-clipboard-target], [data-clipboard-text]');
+  clipboard.on('success', genericSuccess);
+  clipboard.on('error', genericError);
+
+  /**
+   * This a workaround around ClipboardJS limitations to allow the context-specific copy/pasting
+   * of plain text or GFM. The Ruby `clipboard_button` helper sneaks a JSON hash with `text` and
+   * `gfm` keys into the `data-clipboard-text` attribute that ClipboardJS reads from.
+   * When ClipboardJS creates a new `textarea` (directly inside `body`, with a `readonly`
+   * attribute`), sets its value to the value of this data attribute, focusses on it, and finally
+   * programmatically issues the 'Copy' command, this code intercepts the copy command/event at
+   * the last minute to deconstruct this JSON hash and set the `text/plain` and `text/x-gfm` copy
+   * data types to the intended values.
+   */
+  $(document).on('copy', 'body > textarea[readonly]', (e) => {
+    const clipboardData = e.originalEvent.clipboardData;
+    if (!clipboardData) return;
+
+    const text = e.target.value;
+
+    let json;
+    try {
+      json = JSON.parse(text);
+    } catch (ex) {
+      return;
+    }
+
+    if (!json.text || !json.gfm) return;
+
+    e.preventDefault();
+
+    clipboardData.setData('text/plain', json.text);
+    clipboardData.setData('text/x-gfm', json.gfm);
+  });
+}