feature-matrix.js

const range = require('lodash.range');
const padStart = require('lodash.padstart');

const featureIndex = (features, enabledFeatures) => parseInt(
  features.map(feature => enabledFeatures[feature] ? '1' : '0').join(''),
  2
);

const powerSet = features => range(Math.pow(2, features.length));

const indexToFeatures = features => index => Array.from(
    padStart(index.toString(2), features.length, '0')
).reduce(
    (enabledFeatures, bit, i) => Object.assign(enabledFeatures, {
        [features[i]]: bit === '1'
    }),
    {}
);

const generateMatrix = features => powerSet(features).map(indexToFeatures(features));

module.exports = (features, generateFeature) => {
  const matrix = generateMatrix(features).map(generateFeature);
  
  return enabledFeatures => matrix[featureIndex(features, enabledFeatures)];
}