How to use the pouchdb-md5.stringMd5 function in pouchdb-md5

var promiseForView = sourceDB.info().then(function (info) {

    var depDbName = info.db_name + '-mrview-' +
      (temporary ? 'temp' : stringMd5(viewSignature));

    // save the view name in the source db so it can be cleaned up if necessary
    // (e.g. when the _design doc is deleted, remove all associated view data)
    function diffFunction(doc) {
      doc.views = doc.views || {};
      var fullViewName = viewName;
      if (fullViewName.indexOf('/') === -1) {
        fullViewName = viewName + '/' + viewName;
      }
      var depDbs = doc.views[fullViewName] = doc.views[fullViewName] || {};
      /* istanbul ignore if */
      if (depDbs[depDbName]) {
        return; // no update necessary
      }
      depDbs[depDbName] = true;
      return doc;

function getMd5() {
    return md5 || (md5 = stringMd5(JSON.stringify(requestDef)));
  }

function rev(doc, deterministic_revs) {
  var clonedDoc = clone(doc);
  if (!deterministic_revs) {
    return uuid.v4().replace(/-/g, '').toLowerCase();
  }

  delete clonedDoc._rev_tree;
  return stringMd5(JSON.stringify(clonedDoc));
}