Good code is following 3 main concepts:
- Readability – code is generally clean, others understand your code.
- Scalability – can the code perform good with small amount of elements compared to big amount of elements? Can the code be easily scaled horizontally? In general it covers different areas, from algorithm prospective where developer should care about Big O notation to high level architectural things.
- Evolutionary architecture – code must be easy changeable/evolving over new requirements.