Architecture & practice·Design, structure and tradeoffs
the code for one job is spread over four files, and each of those files also does three unrelated jobs.
Cohesion
Also calledhigh cohesion, low cohesion
How much the things inside one module belong together. High cohesion means a module has one reason to exist and everything in it serves that reason; low cohesion means the module is a drawer. It matters because cohesion is what makes a boundary findable: when the code that changes together lives together, a feature is one file to open rather than a search across the repository.