Currying article

compose-full.js

// Data example
const items = [{name: 'Bruce' }, {name: 'Fabs'}, {name: 'Bruce'}, {name: 'Gaby'}];

/**
 * @description Filter by one where condition
 * @param w Where condition function
 * @returns {Function} filter function
 */
const filter = w => a => a.filter(w);

/**
 * @description Create a where condition function
 * @param k Criteria key name
 * @param v Criteria value
 * @returns {Function} Where condition function
 */
const where = (k, v) => i => i[k] === v;

/**
 * @description Create a map function
 * @param fnMap Function to set on map callback
 * @returns {Function} Map function
 */
const map = fnMap => f => f.map(fnMap);

/**
 * @description Create a modification function
 * @param k Key to set any value
 * @param v Value to set
 * @returns {Function} Modification function
 */
const applier = (k, v) => x => x[k] = v;

/**
 * @description Compose function to compose functions
 * @param fns Functions to reduce on composition
 * @returns {Function} Compose function
 */
const compose = (...fns) => x => fns.reduceRight((f, m) => m(f), x);

// Age and lastname compose function to apply changes
compose(
  map(applier('age', 33)),
  filter(where('name', 'Bruce'))
)(items);
compose(
  map(applier('lastname', 'Roque')),
  filter(where('name', 'Fabs'))
)(items);

// Print changes
console.log(items);