nodejs nedb encapsulation library and usage examples

const Datastore = require('nedb');
function DB(database) {
  let options = {
    filename: database,
    autoload: true,
  };
   = new Datastore(options);
}
 = function(offset, limit) {
   = offset || 0;
   = limit || 15;
  return this;
}
 = function(orderby) {
   = orderby;
  return this;
}
 = function(query, select) {
  return new Promise((resolve, reject) => {
    let stmt = (query || {});
    if ( !== undefined) {
      ();
    }
    if ( !== undefined) {
      ().limit();
    }
    if (select != undefined) {
      (select || {});
    }
    ((err, docs) => {
      if (err) {
        return reject(err);
      }
      resolve(docs);
    })
  })
};
 = function(query, select) {
  return new Promise((resolve, reject) => {
    let stmt = (query || {});
    if ( !== undefined) {
      ();
    }
    if (select != undefined) {
      (select || {});
    }
    ((err, doc) => {
      if (err) {
        return reject(err);
      }
      resolve(doc);
    })
  })
}
 = function(values) {
  return new Promise((resolve, reject) => {
    (values, (err, newDoc) => {
      if (err) {
        return reject(err);
      }
      resolve(newDoc);
    })
  })
}
 = function(query, values, options) {
  return new Promise((resolve, reject) => {
    (query || {}, values || {}, options || {}, (err, numAffected) => {
      if (err) {
        return reject(err);
      }
      resolve(numAffected);
    })
  });
}
 = function(query, options) {
  return new Promise((resolve, reject) => {
    (query || {}, options || {}, (err, numAffected) => {
      if (err) {
        return reject(err);
      }
      resolve(numAffected);
    })
  });
}
 = (database) => {
  return new DB(database);
}

const db = require('./libs/nedb')('testdb');
(async function() {
 await ({number: 12});
 await ({number: 11});
 await ({number: 13});
 let res = await ({number: -1}).limit(0, 2).find();
 (res);
})();

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