How to use the pouchdb-json.safeJsonStringify function in pouchdb-json

function encodeMetadata(metadata, winningRev, deleted) {
  return {
    data: safeJsonStringify(metadata),
    winningRev: winningRev,
    deletedOrLocal: deleted ? '1' : '0',
    seq: metadata.seq, // highest seq for this doc
    id: metadata.id
  };
}

const stringifyValue = value => {
  if (value === null) return ''
  if (value === undefined) return ''

  return safeJsonStringify(value)
}

if (revsToCompact.length) {
        compactRevs(revsToCompact, id, tx);
      }

      docInfo.metadata.seq = seq;
      var rev = docInfo.metadata.rev;
      delete docInfo.metadata.rev;

      var sql = isUpdate ?
      'UPDATE ' + DOC_STORE +
      ' SET json=?, max_seq=?, winningseq=' +
      '(SELECT seq FROM ' + BY_SEQ_STORE +
      ' WHERE doc_id=' + DOC_STORE + '.id AND rev=?) WHERE id=?'
        : 'INSERT INTO ' + DOC_STORE +
      ' (id, winningseq, max_seq, json) VALUES (?,?,?,?);';
      var metadataStr = safeJsonStringify(docInfo.metadata);
      var params = isUpdate ?
        [metadataStr, seq, winningRev, id] :
        [id, seq, seq, metadataStr];
      tx.executeSql(sql, params, function () {
        results[resultsIdx] = {
          ok: true,
          id: docInfo.metadata.id,
          rev: rev
        };
        fetchedDocs.set(id, docInfo.metadata);
        callback();
      });
    }
  }

tx.executeSql(sql, [docId], function (tx, result) {
        var metadata = safeJsonParse(result.rows.item(0).metadata);
        traverseRevTree(metadata.rev_tree, function (isLeaf, pos,
                                                           revHash, ctx, opts) {
          var rev = pos + '-' + revHash;
          if (revs.indexOf(rev) !== -1) {
            opts.status = 'missing';
          }
        });

        var sql = 'UPDATE ' + DOC_STORE + ' SET json = ? WHERE id = ?';
        tx.executeSql(sql, [safeJsonStringify(metadata), docId]);
      });