filters.js

#!/usr/bin/env babel-node
import _ from 'lodash/fp'

const filters = {
  // cities
  sea: true,
  nyc: false,
  // experience levels
  beginner: true,
  intermediate: true,
  advanced: false,
  // formats
  workshop: true,
  part: true,
  full: false,
}

const courseListings = [
  { cityCode: 'sea', name: '101', exp: 'beginner', format: 'workshop' },
  { cityCode: 'sea', name: '201', exp: 'advanced', format: 'part' },
  { cityCode: 'nyc', name: '102', exp: 'intermediate', format: 'workshop' },
]

const pickTrue = _.pickBy((f) => f)
const trueFilters = Object.keys(pickTrue(filters))
const filterCourses = (attribute) => _.includes(attribute, trueFilters)

const byCity = (c) => filterCourses(c.cityCode)
const byExp = (c) => filterCourses(c.exp)
const byFormat = (c) => filterCourses(c.format)

const filteredCourses = _.intersection(
  courseListings.filter(byExp),
  courseListings.filter(byCity),
  courseListings.filter(byFormat)
)

console.log(filteredCourses)