Duplication in css selectors, SCSS

Question

Let's say I have such style definitions:

.a.b   { ... }
.a.b.c { ... }

Is there a way to avoid .ab part duplication using SASS/SCSS?

Answer 1

Nest the .abc rule within .ab and replace the first part with the & combinator :

.a.b {
    ...
    &.c { ... }
}