Getting started

Intersect ships three import subpaths, layered so dependencies point down. Reach for the one that matches the question you have.

Import	Reach for it when	Runtime deps
@sksizer/intersect	You hold glob strings and want the friendly, set-aware surface.	none
@sksizer/intersect/segments	You already have pre-split segment arrays and want the pure core.	none
@sksizer/intersect/fs	You need the concrete files on disk that fall in a scope.	tinyglobby

The dependency boundary is the entry-point split itself. The path API and the segment core pull zero runtime dependencies; only @sksizer/intersect/fs — the sole layer that reads disk — pulls a globber. Import it only when you need real files.

A first call

import { intersects } from "@sksizer/intersect";

intersects("src/**/*.ts", "src/api/handler.ts");
intersects("src/api/**", "src/web/**");

A	B	Result	Why
src/**/*.ts	src/api/handler.ts	true	the file is inside the glob
src/api/**	src/web/**	false	disjoint subtrees

intersects is the load-bearing primitive. Every other question in the library is a shape over it.

One string or a set — on either side

An array is the union of its patterns; a single string is a one-element set. The same primitives take whichever shape you already hold, on either argument.

import { intersects } from "@sksizer/intersect";

intersects(["src/api/**", "src/db/**"], "src/db/pool.ts");
intersects(["src/api/**"], ["docs/**", "src/**/*.md"]);
intersects(["a/**"], ["b/**", "c/**"]);

A	B	Result	Why
["src/api/**", "src/db/**"]	"src/db/pool.ts"	true	matches the 2nd of the set
["src/api/**"]	["docs/**", "src/**/*.md"]	true	src/api/x.md is common
["a/**"]	["b/**", "c/**"]	false	no shared path anywhere

The pairwise question (A vs. B) is polynomial, so the API stays pairwise and one-vs-set — it never asks the intractable many-pattern question. Next: the pattern dialect and the primitives.