Bugs in software is a very common problem, code reviews can help to catch bugs early on and detect which code is the most complex and may introduce bugs but when the code base is very large it can be costly to review all the code. Cyclomatic complexity can be used to give an indication of how complex the system source code is and help the developers to select which code they should review. But when measuring cyclomatic complexity on code written according to the functional paradigm, McCabe’s formula will not be sufficient since it is a formula most suitable for imperative code. Therefore we are making adaptations to a formula suited for pure functional languages in order to fit functional JavaScript. We are using an inductive empirical quantitative measurement method to calculate cyclomatic complexity on a directed graph implementation in order to define adaptations for functional JavaScript. Our results show a working adapted version of the formula. We have measured on a graph implemented in Haskell and on a corresponding functional JavaScript version which results in a cyclomatic complexity difference at only 0.375.

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Context: Node.js is an established web framework built using JavaScript. As a result, there are a wide variety of frameworks that have emerged that specialize in different quality attributes and functionalities. Some of which are heavily geared to performance and benchmarking while others might focus on security, availability, robustness, etc. Objectives: The project aims to explore different Node.js server-side frameworks and determine their maintainability using metrics such as Halstead metrics, Maintainability index, source line of code as well as Logical source lines of code. This thesis also explores if there is a correlation between the quality attributes maintainability and performance. Realization: In order to explore the different quality attributes, the thesis relied upon experiments and a literature review. The hierarchical method in this thesis was first to examine their performance, later examine their overall maintainability. Examined is also the impact of comments and how they can affect the results of the maintainability index Results: The results indicate all the selected frameworks have a low-to borderline medium cyclomatic complexity, also a high degree of maintainability using two different 3 metric maintainability index formulas. The latency tests indicate the different frameworks produce similar performance results. Conclusion: Concluded in this thesis is, there seems to be no relationship between both lines of code, logical lines of code, and cyclomatic complexity. There also seems to be no correlation between Halstead volume and the overall maintainability index for both the 3 metric formulas used. There is a slight indication of a relationship between Halstead Effort and Cyclomatic Complexity using one of the 3 metric formulas i.e., as the cyclomatic complexity decreases the overall maintainability (using Halsted’s effort instead of Halstead’s volume) increases.

Viljan att hålla en hög kvalitet på den kod som skrivs vid utveckling av system och applikationerär inte något nytt i utvecklingsvärlden. Flera större företag använder sig av olika mått för attmäta kvaliteten på koden i sina system med målet att hålla en hög driftsäkerhet.Trafikverket är en statlig myndighet som ansvarar för driften av bland annat de system somhåller igång Sveriges järnvägsnät. Eftersom systemen fyller en viktig del i att säkra driften ochse till att tågpositioner, planering av avgångar och hantering av driftstörningar fungerar dygnetrunt för hela landet anser de att det är viktigt att sträva efter att hålla en hög kvalitet påsystemen.Syftet med det här examensarbetet var att ta reda på vilka mått som kan vara möjliga attanvända under systemutvecklingsprocessen för att mäta kvaliteten på kod och hur måtten kananvändas för att öka kvaliteten på IT-lösningar. Detta för att redan på ett tidigt stadie kunnamäta kvaliteten på den kod som skrivs i både befintliga och nyutvecklade system.Studien är en fallstudie som utfördes på Trafikverket, de olika måtten som undersöktes varcode coverage, nivån på maintainability index och antalet inrapporterade incidenter för varjesystem. Mätningar utfördes på sju av Trafikverkets system som i analysen jämfördes motantalet rapporterade incidenter. Intervjuer utfördes för att ge en bild över hur arbetssättet vidutveckling kan påverka kvaliteten. Genom litteraturstudier kom det fram ett mått som inte kundeanvändas praktiskt i det här fallet men är högst intressant, detta är cyclomatic complexity somfinns som en del av maintainability index men som även separat påverkar möjligheten att skrivaenhetstest.Resultaten av studien visar att måtten är användbara för ändamålet men bör inte användassom enskilda mått för att mäta kvalitet eftersom de fyller olika funktioner. Det är viktigt attarbetssättet runt utveckling genomförs enligt en tydlig struktur och att utvecklarna både harkunskap om hur man arbetar med enhetstest och följer kodprinciper för strukturen. Tydligakopplingar mellan nivån på code coverage och inflödet av incidenter kunde ses i de undersöktasystemen där hög code coverage ger ett lägre inflöde av incidenter. Ingen korrelation mellanmaintainability index och incidenter kunde hittas. / The desire to ascertain a high level of quality on the code written during the development of systems and applications is not something new in the system development world. Several larger companies use different kinds of metrics to measure the quality of the code in their systems with the goal of maintaining high reliability and quality.Trafikverket is a government authority responsible for the operation of the system that keeps the Swedish railroad running. Their systems play an important part in ensuring the operation and to ensure that train positions, the planning of departures and error handling works around the clock for the entire country, they find it important and strive to maintain the high quality of the systems.The aim of this thesis was to find out which measurements may be possible to use during the system development process to measure the quality of the code and how measurements can be used to increase the quality of IT solutions. It should be possible to measure the quality of the code that is written in both existing and newly developed systems at an early stage. The study is a case study conducted at Trafikverket, the metrics that were examined were code coverage, the level of maintainability index and the number of reported incidents for each system. Measurements were performed on seven of Trafikverket's systems. In the analysis the measurements were compared to the number of reported incidents. Interviews were conducted to provide a picture of how the operation of the development may affect the quality. Through literature studies we discovered a metric that could not be used practically in this case, this was cyclomatic complexity, it is available as part of the maintainability index, but also separately affects the ability to write unit tests. The results of the study show that the measurements are useful for this purpose but should not be used as individual metrics to measure quality because they all have their own function. A clear link between the level of the code coverage and the number of incidents could be observed in the investigated systems where high code coverage provides a lower rate of incidents. No correlation between maintainability index and incidents could be found.

Learning to program is acknowledged to be difficult; programming is a complex intellectual activity and cannot be learnt without practice. Research has shown that first year IT students presently struggle with setting up compilers, learning how to use a programming editor and understanding abstract programming concepts. Large introductory class sizes pose a great challenge for instructors in providing timely, individualised feedback and guidance for students when they do their practice. This research investigates the problems and identifies solutions. An interactive and constructive web-based programming environment is designed to help beginning students learn to program in high-level, object-oriented programming languages such as Java and C#. The environment eliminates common starting hurdles for novice programmers and gives them the opportunity to successfully produce working programs at the earliest stage of their study. The environment allows students to undertake programming exercises anytime, anywhere, by "filling in the gaps" of a partial computer program presented in a web page, and enables them to receive guidance in getting their programs to compile and run. Feedback on quality and correctness is provided through a program analysis framework. Students learn by doing, receiving feedback and reflecting - all through the web. A key novel aspect of the environment is its capability in supporting small &quotfill in the gap" programming exercises. This type of exercise places a stronger emphasis on developing students' reading and code comprehension skills than the traditional approach of writing a complete program from scratch. It allows students to concentrate on critical dimensions of the problem to be solved and reduces the complexity of writing programs.

Web applications are subject to intense market forces, fast delivery and rapid requirement and code change. These are the factors that make maintainability a significant concern in any and especially web application development. In this report we develop a functional equivalent prototype from an existing Angular app, using ReactJs and afterward compare their maintainability as defined by ISO/IEC 25010. The maintainability comparison is made by calculating maintainability index for each of the applications using Plato analysis tool. The results do not show a significant difference in the calculated value of the final products. Source code analysis shows that changes in data flow need more modification in the Angular app, but with the objective oriented approach provided by Angular, we can have smaller chunks of code and thus higher maintainability per file and respectively a better average value. We conclude that regarding the lack of research and models in this area, MI is a consistent measurement model and Plato is a suitable tool for analysis. Though maintainability is highly bounded to the implementation, functionalities which are provided by the Angular framework as a bundle is more appropriate for large enterprises and complex products where React works better for smaller products.