Remove duplicate entries from an exported Bitwarden .json vault

bitwarden-dedup.html

<input type="file" accept=".json">
<a style="display: none;"></a>

<script>
  /**
   * The following code should remove duplicate items within a .json vault that was
   * exported from Bitwarden v1.31.3 and maybe higher (needs more testing).
   * Once the right .json is provided, it will prompt a dialog to save a non-formatted out.json
   * 
   * Copyright 2022 ZReC & others
   * 
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
   * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
   * PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
   * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
   * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
   * OR OTHER DEALINGS IN THE SOFTWARE.
  */
  const file = document.querySelector('input');
  file.addEventListener('change', e => {
    for (const f of e.target.files) {
      const read = new FileReader();
      read.addEventListener('load', async e => {
        const str = e.target.result;
        const json = JSON.parse(str);

        if ('items' in json) {
          const hash = {};
          for (const prop in json.items) {
            const item = json.items[prop];
            const id = item.id;
            delete item.id;

            const itemhash = new TextDecoder()
              .decode(
                await crypto.subtle.digest(
                  'sha-256',
                  new TextEncoder()
                    .encode(JSON.stringify(item))
                )
              );

            if (!(itemhash in hash)) {
              item.id = id;
              hash[itemhash] = item;
            }
          }

          const final = [];
          for (const prop in hash) {
            final.push(hash[prop]);
          }
          json.items = final;

          const send = document.querySelector('a');
          var blob = new Blob([JSON.stringify(json)], { type: 'text/plain' });
          send.href = window.URL.createObjectURL(blob);
          send.download = 'out.json';
          send.dataset.downloadurl = ['text/plain', send.download, send.href].join(':');

          send.click();
        }
      });

      read.readAsText(f);
    }
  });
</script>