The first step of debugging a deployed application is to reproduce the reported bug. But bugs that cause unpredictable behaviors without crashing the applica- tion can be difficult to reproduce, because the developer has to rely on bug-re- ports issued by users. The goal of this thesis has been to develop a diagnostic tool which makes user-reported bugs easier to reproduce. More specifically, the goal has been to develop such a tool for React Native applications implement- ing Redux, taking into consideration both state-data stored in Redux stores and React Native components. Requirements for the diagnostic tool were laid out and partitioned into proto- types that were implemented separately in iterations and then merged into the resulting tool. Requirements were also drawn for three sample applications to test and evaluate the tool, as well as a back-end to prove the tool's capability in uploading and downloading state-data from a server. The thesis resulted in a diagnostic tool that's imported into an already existing code-base as a third-party library, and which collects the complete state of the reported application instance and delivers it to the developer as a single JSON document. The tool can then inject the state-data into a fresh instance of the ap- plication to make it identical to the malfunctioning instance reported by the user; a process referred to as "reviving". Redux stores demonstrated state-over- write protection which complicates state-injection. A study was performed to compare the impact this difference has on performance. As expected, the study revealed that the diagnostic tool takes marginally longer to revive state-data in Redux stores for this reason.

Nowadays almost everyone has a smart phone. In addition, as more people use smart phones more applications are being developed for smart phones. Each operating system on the smart phone market has its own applications. Up until a few years ago, developers had to develop an exclusive application for each operating system in order to cover the whole market. A number of cross-platform frameworks have emerged. These frameworks enable developers to use one code base for every operating system. To be able to use most of the code for all platforms makes it easier to maintain and evolve the application. Two of the frameworks that allow cross-platform development are React Native and Ionic. The purpose and goal of the thesis is to evaluate if Ionic 2 is eligible to use as a cross-platform framework in terms of performance. The method used to achieve the goal is based on replication. An application made in React Native is replicated by using Ionic 2. The applications are then evaluated with focus on performance. The applications are evaluated using AndroidViewClient and Trepn profiler. AndriodViewClient is run outside of the OS of the Android device and can control the GUI of a device. AndroidViewClient is used to automate the tests. The metrics used for evaluating the performance are CPU load, memory usage, battery power usage, the size of the application and the size of the Android package kit. Trepn profiler is an application that is installed on the device. Trepn profiler has access to the hardware of the device and is therefore used to measure the first three mentioned metrics.

MVC architecture is one of the most known and used architecture for application development, for both web and desktop based application. New architecture evolved though thanks to the fast-growing industry and it brings new practices that are much more convenient to use. The main goal of this theses is to describe how Redux library, which is based on this new architecture, is used for application development. Redux is only a state management library, another library is needed for creating the user interface. It is possible to create the user interface from the scratch but it takes a lot of time and it is difficult to scale. React library is possibly the most favorite library for creating UI and it works well together with Redux. For these reasons, React was selected as the UI library that will be used in this thesis. While theoretical part of this thesis is focused on describing principles Redux and React libraries are based upon and the best practices for using these libraries, practical part is focused on using the theoretical knowledge in the real world, demonstrated on the web application for invoicing. Development of the invoicing system is described in a way that demonstrates to the reader how to approach web application development, what does it contain and where to start.

The aim of this diploma thesis is to implement a presentation layer for the Reminiscence Computer Therapy application. Reminiscence Therapy involves the discussion of the past memories and it is believed to help people with dementia to improve their well-being and sustain their memories. Computer Reminiscence Therapy involves technology in this therapy. The research introduces into Dementia and Reminiscence Therapy with and without using technologies. The application developed as part of this diploma thesis uses picture upload and speech recognition techniques for the memory input. This is used to support remembering of past memories and to increase discussion. The application can be used with or without the carer as well as with friends and family members. The six most important requirements on the developed application are the speech recognition, picture upload, asking questions about the previous recordings, asking questions about tagged friends, using old stories for discussion and presenting the statistics. The application was developed as a part of the competition made by AngelHack organization. Presentation, business and persistence layers of the application are discussed in this diploma thesis as well as user manual and persistence layer implementation of the requirements. The presentation layer was developed using React framework for JavaScript. Other libraries have to be used as well with the most important being Redux library for storing application state. This library affected the structure of the persistence layer.

The goal with this project has been to develop an application where a user can create and manage tournaments that uses the Swiss format. The application would consist of one display page that can be used to show the current state of the tournament for all the competitors, and one admin page where a user can update match results and generate a new round of matches. The application has been developed with Node.js on the server side and the JavaScript library React on the client side. All the React code is written in the modern way with functional components and the usage of React Hooks. The document based database MongoDB has been used for the application. Real time-updates has been implemented with the library Socket.IO The project has led to a well-functioning application where a user can create och manage a tournament and where all the updates are done in real time in a neat and smooth way. The creator of the tournament can share both the admin page and the display page to other people who want to see the tournament result by sharing the link to the specific tournament. / Målet med denna projektuppgift har varit att utveckla en applikation där användare kan skapa och hantera turneringar som använder sig av Swiss-formatet. Applikationen skulle bestå av dels en uppvisningssida som kan användas till att visa upp turneringens aktuella resultat för medtävlande och dels en administrationssida där en användare kan uppdatera matchresultat och generera en ny omgång matcher. Applikationen har utvecklats med Node.js till serversidan och JavaScript-biblioteket React på klientsidan. All React-kod är skriven med funktionskomponenter och React Hooks, vilket är det moderna sättet att utveckla i React på. Som databas till applikationen har en dokumentbaserad databas använts: MongoDB. Realtidsuppdateringarna har möjliggjorts med hjälp av biblioteket Socket.IO. Projektet har lett till en väl fungerande applikation där en användare kan skapa och hantera en turnering, och där alla uppdateringar sker i realtid på ett snyggt och smidigt sätt. Skaparen av turneringen kan dela med sig både administrationssidan och uppvisningssidan till andra personer som vill se turneringsresultaten genom att dela länken till den specifika turneringen.

Blazor WebAssembly is a new framework that was released in May 2020 that makes it possible to build client-side web applications using C# instead of using JavaScript for its frontend. The most popular web frameworks today are JavaScript based frameworks. This study aims to find out if Blazor is a viable option to use for developing web applications and if it is a well-established framework compared to JavaScript frameworks. To evaluate Blazor, a comparison is performed between Blazor and React on six criteria. The criteria are lines of code, cyclomatic complexity, state management, debugging tools, community, and libraries. To answer the criteria two applications was developed, one in the React framework and one in the Blazor framework. Besides the two applications, literature was gathered to answer the criteria. The results from the comparison showed Blazor was a Viable option to use for the development of web applications and that it has become established as a framework when taken its age in to consideration.

This thesis is focused on requirements analysis of a sawmill company for a new timber stock evidence system and based on the analysis describes the process of development of the system. The process covers architecture and structure design as well as data storage solution. Apart from the development stage itself, it also covers the implementation of the system in the company’s environment and economic evaluation of the process. The system is being developed using the Javascript programming language and uses modern technologies such as React, Node.js and MongoDB.

The thesis deals with the design and development of a tool for easy search of flight connections for Pelikantravel.com s.r.o. The aim of this work is to develop a tool that will allow operation in a limited Internet connection and will support user feedback. The first part of the thesis describes the analysis of suitable technologies and platforms for the resulting tool. The practical part deals with the issue of user experience and with the related user interface design. In this section, the basic functionality of the tool is described according to the use case analysis. Furthermore, the work describes in detail the implementation of the whole tool and in the end is devoted to testing the resulting tool.

For several decades, market fragmentation caused by different operating systems has been complicating and overpricing the process of creating new applications. Unified development for multiple platforms does not only save time and expenses, but also enables to reach a far wider audience. This work presents the topic of a cross-platform mobile development and analyzes the development of the market for currently the two most prevalent operating systems – Android and iOS. The results of the analysis are used to design and create a multiplatform tool intended to monitor immunopathologic reactions. The work also includes a marketing plan and expected economic valuation once the developed application is introduced to the market.

This final thesis addresses the approach of standards and software for calculation of pressure vessels loaded by external pressure and a design of own calculation software, including a demonstration on chosen geometry. The approaches of standards and software are solved in the form of research. The practical part describes the developed software, selected technologies for development and results of the demonstration. The demonstration was carried out on two geometries and was successful.