<script>
  import { Pane, Splitpanes } from 'svelte-splitpanes';

  import Button from '$comp/Button.svelte';

  function onClick() {
    visible = !visible;
  }

  let visible = true;
</script>

<Button on:click={onClick}>{visible ? 'Hide' : 'Show'}</Button>

<Splitpanes style="height: 400px">
  <Pane>
    <span>1</span>
  </Pane>
  {#if visible}
    <Pane>
      <span>2</span>
    </Pane>
  {/if}
  <Pane>
    <span>3</span>
  </Pane>
</Splitpanes>