My Ramda helpers

ramda-utils.js

const R = require('ramda');

const mapIndexed = R.addIndex(R.map);

// notEmpty : a -> Bool
const notEmpty = R.converge(R.compose(R.not, R.or), [isNaN, R.isEmpty]);

// buildDict : String -> [{ k: v }] -> { k: v }
const buildDict = R.uncurryN(2, key => R.pipe(
  R.map(R.compose(R.toLower, R.prop(key))),
  R.uniq,
  R.filter(R.compose(R.not, R.isEmpty)),
  mapIndexed(R.flip(R.objOf)),
  R.mergeAll
));

// pickByRegExp : RegExp -> Object -> Object
const pickByRegExp = RegExp => R.pickBy(R.compose(R.test(RegExp), R.nthArg(1)));

// featurePropertyLens : Int -> String -> Lens s a
const featurePropertyLens = (index, property) => R.compose(
  R.lensProp('features'),
  R.lensIndex(index),
  R.lensPath(['properties', property])
);