Towards a catalog of code defects for ScratchJr

Abstract

Learning to program is a complex task that involves multiple aspects. One of the skills developed with programming expertise is coding style. Cultivating good programming habits not only improves code quality but also fosters a deeper understanding of the language. In recent years, increasing attention has been given to code quality and defects from the very first programming course. This trend can be integrated into the training of pre-university teachers, which is essential for introducing computer science into school curricula. This paper presents a catalog of code defects for the block-based language ScratchJr. These defects can be shown to pre-service teachers to raise awareness of potential issues in the programs they create. The proposed defects are grouped into four categories: dead code, unpredictable behavior, ineffective code, and poor programming style. They were identified through a combination of the authors’ experience with the language and the analysis of projects developed by trainee teachers. The paper concludes with suggestions for future work.