In the following research review, 57 articles were analysed to get an insight into research in the field of computational thinking and programming in K-12. The results show that empirical research regarding programming and computational thinking is prevalent in the USA and Greece. The articles were published in 43 different academic journals. A fast-growing number of articles published in the research field during 2006-18 indicate growing interest. The articles were analysed and clustered into seven strands: (1) Evaluating digital resources, (2) Assessment, (3) Improving students' academic performance through programming, (4) Gender and equity, (5) Games -- as a method to learn programming, (6) Attitudes and motivations, and (7) Teachers' competencies and teaching. An extensive focus is on the evaluation of different technical solutions as well as pedagogical methods. Implications for teaching and learning programming and developing computational thinking skills are discussed.