How to use the bcrypt.genSaltSync function in bcrypt

import bcrypt from 'bcrypt';
import jwt from 'jsonwebtoken';
import db from '../db/index';

const saltRounds = 10;
const salt = bcrypt.genSaltSync(saltRounds);
const SECRET_KEY = 'secretkey23456';
const expiresIn = 24 * 60 * 60;

const User = {
  register(req, res) {
    if (!req.body.email || !req.body.password || !req.body.fname || !req.body.lname) {
      return res.status(400).send({ message: 'All fields are required' });
    }

    // Check if existing
    const query = 'SELECT * FROM users WHERE email = $1';
    db.query(query, [req.body.email])
      .then((result) => {
        if (result.rows.length > 0) {
          return res.status(400).send({ message: 'Email already exists' });
        }

encryptPassword(receivedPassword)
    {
        this.saltRounds = 10;
        // generate the password hash:
        let salt = bcrypt.genSaltSync(this.saltRounds);
        return bcrypt.hashSync(receivedPassword, salt);
    }

this.afterLoginFn = function( res, user ){
    res.redirect('/');
  }
  
  this.dashboard = new Dashboard( this, this.config.signups )
  this.waitlist = false;
  this.authentication = new Auth( this, this.config.authentication );

  if( this.config.signups ){
    this.signups( this.config.signups );
    this.waitlist = this.config.signups.waitlist;
  }

  if(this.config.superUser){
    var salt = bcrypt.genSaltSync(10),
        plainPassword = this.config.superUser.password,
        password = bcrypt.hashSync( this.config.superUser.password, salt );
    this.config.superUser.password = password;
    this.db.createSuperUser( this.config.superUser );
    this.config.superUser.password = plainPassword;
  }


  // critical
  this.dashboard.addAuth( this.authentication );
  

}

function strCryptSync(str) {
  return bcrypt.hashSync(str, bcrypt.genSaltSync(10));
}

exports.hashPassword = password => {
  const salt = bcrypt.genSaltSync();
  const hash = bcrypt.hashSync(password, salt);
  return hash;
};

}).set(function (password) {
        this._password = password;
        var salt = this.salt = bcrypt.genSaltSync(10);
        this.hash = bcrypt.hashSync(password, salt);
    });

CLI.prototype._generateSalt = function (config) {
  config.salt = bcrypt.genSaltSync()
}

function hashPass(user) {
    const salt = bcrypt.genSaltSync(10);
    user.set('password', bcrypt.hashSync(user.password, salt));
  }

encryptPassword: function(password) {
                    if (!password) return '';
                    return bcrypt.hashSync (password, bcrypt.genSaltSync(SALT_WORK_FACTOR));
                }
            }

function generateHash(password) {
  return bcrypt.hashSync(password, bcrypt.genSaltSync(10));
}