Implement copy for non-standard browsers. Fix flaky embed copy

web/components/share-embed-button.tsx

@@ -4,6 +4,7 @@ import { Menu, Transition } from '@headlessui/react'
 import { Contract } from '../../common/contract'
 import { contractPath } from '../lib/firebase/contracts'
 import { DOMAIN } from '../../common/envs/constants'
+import { copyToClipboard } from '../lib/util/copy'
 
 export function ShareEmbedButton(props: { contract: Contract }) {
   const { contract } = props
@@ -14,15 +15,16 @@ export function ShareEmbedButton(props: { contract: Contract }) {
 
     const embedCode = `<iframe width="560" height="405" src="${src}" title="${title}" frameborder="0"></iframe>`
 
-    if (navigator.clipboard) navigator.clipboard.writeText(embedCode)
+    copyToClipboard(embedCode)
   }
 
   return (
-    <Menu as="div" className="relative z-40 flex-shrink-0" onClick={copyEmbed}>
-      <Menu.Button
-        className="btn btn-xs btn-outline normal-case hover:bg-white hover:text-neutral"
-        onClick={copyEmbed}
+    <Menu
+      as="div"
+      className="relative z-40 flex-shrink-0"
+      onMouseUp={copyEmbed}
     >
+      <Menu.Button className="btn btn-xs btn-outline normal-case hover:bg-white hover:text-neutral">
         <CodeIcon className="w-4 h-4 text-gray-500 mr-1.5" aria-hidden="true" />
         Embed
       </Menu.Button>

web/lib/util/copy.ts

@@ -0,0 +1,38 @@
+// From: https://stackoverflow.com/a/33928558/1592933
+// Copies a string to the clipboard. Must be called from within an
+// event handler such as click. May return false if it failed, but
+// this is not always possible. Browser support for Chrome 43+,
+// Firefox 42+, Safari 10+, Edge and Internet Explorer 10+.
+// Internet Explorer: The clipboard feature may be disabled by
+// an administrator. By default a prompt is shown the first
+// time the clipboard is used (per session).
+export function copyToClipboard(text: string) {
+  if (navigator.clipboard) {
+    navigator.clipboard.writeText(text)
+  } else if (
+    (window as any).clipboardData &&
+    (window as any).clipboardData.setData
+  ) {
+    console.log('copy 2')
+    // Internet Explorer-specific code path to prevent textarea being shown while dialog is visible.
+    return (window as any).clipboardData.setData('Text', text)
+  } else if (
+    document.queryCommandSupported &&
+    document.queryCommandSupported('copy')
+  ) {
+    console.log('copy 3')
+    var textarea = document.createElement('textarea')
+    textarea.textContent = text
+    textarea.style.position = 'fixed' // Prevent scrolling to bottom of page in Microsoft Edge.
+    document.body.appendChild(textarea)
+    textarea.select()
+    try {
+      return document.execCommand('copy') // Security exception may be thrown by some browsers.
+    } catch (ex) {
+      console.warn('Copy to clipboard failed.', ex)
+      return prompt('Copy to clipboard: Ctrl+C, Enter', text)
+    } finally {
+      document.body.removeChild(textarea)
+    }
+  }
+}