Andrej Gajdos - Freelance JavaScript Developer for Hire

React Developer

2018 - 2018

Glofox

Helped deliver a React Native project used for managing fitness studios.
Fixed various bugs and issues in the project.
Optimized the project for the Android platform.

Technologies: React Native, Redux

Principal Software Engineer

2017 - 2018

Saycaster

Designed and built an interactive podcast platform.
Podcasters can upload audio files and add 'spots' to specific moments in their podcasts, which can be anything from links, to social media posts, to other videos or images.
Listeners are engaged with content, such as social media posts or preview of external web pages.
Built a single-page app from scratch with a complex user interface, including user interactions and animations using React.js, Redux, D3.js, Webpack, SVG, and HTML5 Audio.
Designed and developed a RESTful API server using Heroku, Amazon S3, Node.js, Koa, PostgreSQL, and integration with Twitter API.

Technologies: Heroku, Amazon S3, PostgreSQL, JavaScript, Node.js, Koa, Objection.js, Knex.js, React.js, Redux, D3.js, SVG, Webpack, Babel, Twitter API, invisionApp

Pre-sales Engineer

2016 - 2017

ZeroTurnaround

Presented and demonstrated products to potential customers from all over the world.
Demonstrated product features to developer teams and showed how to use them in the development process with a specific workflow, environment, and toolset.
Helped sales associates close deals by presenting our products in specific use-cases.
Trained sales associates in how to effectively present and sell our tools to developer teams and managers.
Assisted customers with installation, troubleshooting, and other customer service for configuration issues.

Technologies: Java

Software Engineer

2015 - 2016

Ataccama

Implemented new features and fixed bugs in enterprise applications used for data quality management and rewrote UI components to use modern technologies.
Designed and implemented the front-end of an interactive application for customer data management.
Designed and implemented server-to-sever communication and server pushes in a GWT application.

Technologies: Java, JavaScript, ES6, React.js, Flux, Immutable.js, Backbone.js, jQuery, Bootstrap, SCSS, Webpack, Gulp, Babel, D3.js, JSP, JSTL, JMS, ActiveMQ, Errai

Java Developer

2013 - 2015

Techniserv, Taranzo

Analyzed, designed, and implemented solutions for gathering and processing structured and unstructured data from social networks and various other sources.
Designed and implemented a module for building and visualizing a social network.

Technologies: Java, JavaScript, Liferay, Spring MVC, Maven, JSP, JSTL, jQuery, Bootstrap, D3.js, Jung, OrietDB, YouTube and Twitter APIs

Software Tester

2012 - 2013

Amberg Group

Executed both manual and automated tests and analyzed the results.
Developed and maintained the whole test infrastructure with automated tests.
Designed test cases, wrote documentation, and reported issues.

Technologies: JavaScript, Python, Ruby

SayCaster (Development)

https://www.saycaster.com/

An interactive podcast platform:

- Podcasters upload their audio and add 5-20 spots to their podcasts
- These spots can be anything from links, to social media posts, to other videos or images
- Listeners can listen and comment on these specific spots

Neo Transfer (Development)

https://github.com/AndrejGajdos/neo-transfer

Neo-transfer allows you to log in with a private key, see balance, and transfer NEO or GAS within TestNet. The project is based on JS SDK for NEO blockchain.

Technologies: Neon.js, React.js, Redux, Redux-Saga, Twitter Bootstrap

Newsfeed Cryptogoods (Development)

https://github.com/AndrejGajdos/newsfeed-cryptogoods

A newsfeed for events on cryptogoods with a single, responsive page.

Technologies: React.js, Redux, Redux-Saga, Twitter Bootstrap

Authenticating Users in SPA using Node, Passport, React and Redux (Development)

https://github.com/AndrejGajdos/auth-flow-spa-node-react

User authentication in a single page application with Node, React, Redux and Koa combined with Passport.

http://andrejgajdos.com/authenticating-users-in-single-page-applications-using-node-passport-react-and-redux/

Nested Datatables (Development)

https://andrejgajdos.github.io/nested-datatables/

jQuery DataTables plugin for rendering nested data tables in rows. Inner tables are independent of the data and layout from the outer table.

Webpack Setup for ES6, React, Sass, and Bootstrap (Other amazing things)

https://github.com/AndrejGajdos/webpack-react

Webpack configuration to bundle ES6, React, Sass, and Bootstrap for production and development.

http://andrejgajdos.com/setting-up-webpack-for-es6-react-sass-and-bootstrap/

Social Graph (Development)

A Liferay portlet to visualize a social network as a directed multigraph. Jung library is used for building the multigraph, which is stored in OrientDB. Visualization and other components are built in D3.js and Bootstrap.

Technologies: Java, JavaScript, Liferay, JSP, Jung, OrientDB, D3.js, Bootstrap

SVG Sprite into PNG (Development)

https://github.com/AndrejGajdos/svg-sprite-to-png

A workflow converts SVG sprite into PNG images utilizing Gulp.

http://andrejgajdos.com/how-to-convert-svg-sprite-into-png-images/

Server Push in GWT Application with Errai (Development)

https://github.com/AndrejGajdos/gwt-errai-messaging

Implementation of server push messages from server to client in GWT application with Errai framework.

http://andrejgajdos.com/first-steps-with-gwt-and-errai-messaging/

Contract Generator Tool (Development)

Some insurance brokers have a list of insurances and clients in XLS format and need to generate various contracts based on a contract template in DOC and DOCx format. The user can set up a database (XLS or XLSx) and required columns, which will be parsed into the contract. The application has a database of insurance in SQLite. The main window contains a list of clients with detailed information, where the user can instantly search clients, add required information (date, overpayment, insurance from database), choose contract templates, and generate a contract (DOC or DOCx) for the client. The UI is built in WPF and ADO.NET is used for parsing data from a Microsoft Excel file.

Technologies: C#/.NET, WPF, SQLite, ADO.NET

Personal Calendar (Development)

https://github.com/AndrejGajdos/personal-calendar

A basic personal calendar application with two view modes (week/month). The application generates log files and uses a MySQL database. The presentation layer is built in Swing and SwingWorker. Connections to the database are developed in JDBC. The project contains simple JSP pages for viewing a list of events and their detailed information.

Technologies: Java, JSP, Swing, SwingWorker, MySQL, JDBC

Guide to Data Synchronization in Microsoft SQL Server (Publication)

https://www.toptal.com/sql/guide-to-data-synchronization-in-microsoft-sql-server

Sharing related information among isolated systems has become increasingly important. There are many methods to choose from to perform that task for SQL Server, but it’s important to know which is better for each use case.

A Guide to Managing Webpack Dependencies (Publication)

https://www.toptal.com/javascript/a-guide-to-managing-webpack-dependencies

The Webpack module bundler processes JavaScript code and all static assets, such as stylesheets, images, and fonts. However, configuring Webpack and its dependencies can be cumbersome and not always a straightforward process, especially for beginners. In this article, Toptal Software Engineer Andrej Gajdos provides a guide with examples on how to configure Webpack for different scenarios and points out the most common pitfalls connected to project dependencies and their bundling when using Webpack.

Languages

JavaScript, Java, SQL, ECMAScript (ES6), SCSS, HTML5, HTML/CSS, CSS, HTML, CSS3, Sass, Object-oriented JavaScript (OOJS), JavaScript 6, Less, C#, Python, PHP, Ruby, C++, C, UML

Libraries/APIs

Underscore.js, Redux-saga, React, Passport.js, D3.js, jQuery, Chai, Immutable.js, JSTL, OpenGL, jQuery Plugins, jQuery UI, Win32 API, Node.js, WinForms, Backbone.js, JDBC, JMS

Paradigms

Model View Controller (MVC), Agile Software Development, Object-relational Mapping (ORM), Software Testing, REST, Functional Programming, Automated Testing, Object-oriented Design (OOD), Object-oriented Programming (OOP)

Storage

JSON, PostgreSQL, SQLite, MySQL, Graph Databases, OrientDB

Other

Front-end, AJAX, UI Development, Software Design, Presentations, Sales, Customer Service, Consultation, Writing, Single-page Applications (SPA), Back-end Development, Web Development, Programming, Technical Consulting, Sales Presentations, Web Scraping, Liferay, ESLint, Data Visualization, BPM, Messaging patterns, Social Networks Development, Data Analysis

Frameworks

Redux, Bootstrap, Koa, Flux, JUnit, Spring MVC, WPF, React Native, .NET, JSP, Swing, Ruby on Rails (RoR)

Tools

Redux Thunk, Webpack, Bower, Gulp.js, Mocha, GitHub, GitHub Pages, Maven, GitLab, Trello, InVision, PostCSS, Knex.js, Babel, ActiveMQ

Platforms

Firebase, Java EE, Windows, Heroku, Linux, Mac OS, WordPress, Amazon

Master's degree in Service Science, Management, and Engineering

2013 - 2015

Masaryk University Brno - Brno

Erasmus exchange student in Master in Innovation and Research in Informatics

2014 - 2014

Polytechnic University of Catalonia - Barcelona

Bachelor's degree in Applied Informatics

2009 - 2013

Masaryk University - Brno