ignore is a tool which implements in pure JavaScript the .gitignore spec.

upsearch is a tool for finding files in parent directories.

Together a micro utility library is born.

# OS or Editor folders
.DS_Store
._*
.cache
.project

# Directories
node_modules
old/
*-old/

var ig = require('local-gitignore')

local-gitignore provides all the methods provided by the ignore library.

var paths = [
  '.DS_STORE',    // filtered out
  'node_modules/bixby/index.js',    // filtered out
  'index.js'   // included
]

ig.filter(paths)  // ['index.js']

paths.filter(ig.createFilter()); // ['index.js']

ig.ignores('.DS_Store') // true
ig.ignores('project/index.js') // false

I was looking for exactly this functionality when I came across the excellent ignore library. So, I'm publishing what past me was looking for in the first place.