dify/web/utils/clipboard.ts

export async function writeTextToClipboard(text: string): Promise<void> {
  if (window.isSecureContext && navigator.clipboard && navigator.clipboard.writeText) {
    try {
      await navigator.clipboard.writeText(text)
      return
    } catch {
      // Fall through to the legacy path when browsers deny Clipboard API access.
    }
  }

  return fallbackCopyTextToClipboard(text)
}

async function fallbackCopyTextToClipboard(text: string): Promise<void> {
  const textArea = document.createElement('textarea')
  textArea.value = text
  textArea.style.position = 'fixed' // Avoid scrolling to bottom
  document.body.appendChild(textArea)
  textArea.focus()
  textArea.select()
  try {
    const successful = document.execCommand('copy')
    if (successful) return Promise.resolve()

    return Promise.reject(new Error('document.execCommand failed'))
  } catch (err) {
    return Promise.reject(convertAnyToError(err))
  } finally {
    document.body.removeChild(textArea)
  }
}

function convertAnyToError(err: unknown): Error {
  if (err instanceof Error) return err

  return new Error(`Caught: ${String(err)}`)
}