SOLID

Five object-oriented design principles collected under one acronym by Robert C. Martin: Single responsibility, Open–closed, Liskov substitution, Interface segregation, Dependency inversion — a module should have one reason to change, be extended without being edited, honor the contract of what it replaces, expose only what a caller needs, and depend on abstractions rather than details

Written for classes, but the ideas survive the translation to components and composables: a Vue component with one reason to change, a slot instead of a fork, a prop interface a caller can fill without knowing the internals, an adapter behind a storage interface rather than an S3 call in a route. The letters are a mnemonic, not a checklist; the principle behind all five is that the parts that change together should live together, and the parts that change separately should not know about each other.