Get the client working as expected with pg 8

/*global require,module,process*/

var postgres = require('pg');

var winston = require('winston');

const {Client} = require('pg');

// create table entries (id serial primary key, key varchar(255) not null, value text not null, expiration int, unique(key));

  // A connection wrapper

  safeConnect: function (callback) {

    postgres.connect(this.connectionUrl, function (err, client, done) {

      if (err) {

        winston.error('error connecting to postgres', { error: err });

        callback(err);

      } else {

    const client = new Client({connectionString: this.connectionUrl});

    const connectionPromise = client.connect();

    const done = () => {};

    connectionPromise.then(() => {

      callback(undefined, client, done);

      }

    }).catch((error) => {

      console.log(error);

      winston.error('error connecting to postgres', {error});

      callback(error);

    });

  }