selector_unify

selector_unify($selector1, $selector2)

Unifies two selectors into a single selector that matches only elements matched by both input selectors. Returns null if there is no such selector.

Like the selector unification done for @extend, this doesn’t guarantee that the output selector will match all elements matched by both input selectors. For example, if .a .b is unified with .x .y, .a .x .b.y, .x .a .b.y will be returned, but .a.x .b.y will not. This avoids exponential output size while matching all elements that are likely to exist in practice.

selector-unify(".a", ".b") => .a.b
selector-unify(".a .b", ".x .y") => .a .x .b.y, .x .a .b.y
selector-unify(".a.b", ".b.c") => .a.b.c
selector-unify("#a", "#b") => null