Headless usage

<EazipTray /> is optional — everything it renders is derived from useEazip()'s task, so any part of it (or all of it) is easy to reimplement in your own design system.

import { useEazip } from '@eazip/react';

function ExportButton({ files }: { files: File[] }) {
  const zip = useEazip();
  const task = zip.task;

  if (!task) {
    return (
      <button disabled={zip.isBusy} onClick={() => zip.download({ files })}>
        Download as ZIP
      </button>
    );
  }

  return (
    <div>
      {task.state === 'processing' ? (
        <>
          {task.progress ? (
            <progress value={task.progress.filesCompleted} max={task.progress.filesTotal} />
          ) : (
            <progress />
          )}
          <button onClick={() => zip.cancel()}>Cancel</button>
        </>
      ) : null}

      {task.state === 'completed' || task.state === 'partial' ? (
        <button onClick={() => zip.downloadAll()}>
          {task.zips.length > 1 ? `Download ${task.zips.length} zips` : 'Save file'}
        </button>
      ) : null}

      {task.state === 'failed' && task.canRetry ? (
        <button onClick={() => zip.retry()}>Try again</button>
      ) : null}
    </div>
  );
}

A few things worth knowing before you build on this:

task.progress is only ever populated for local jobs — cloud jobs poll a session, not a byte stream, so render an indeterminate spinner for task.strategy === 'cloud' instead of a percentage.
task.zips[] carries filename/size/downloadUrl per part; use downloadZip(task.id, index) to trigger one specific part instead of downloadAll().
task.skipped (populated once state is 'partial') is the per-file reason list — see Partial results & errors for what reason means on local versus cloud, where only a count is available.
task.canRetry reflects whether the original request is still replayable — see Persistence & reload-resume for the one case (a restored, backend-created session) where it isn't.

isBusy is just task?.state === 'processing' — reach for it when all you need is a boolean, and task directly for anything richer.