ClassList

classList_v1.js

function ClassList(unwrapFn) {
  this.getClasses = unwrapFn;

  return this;
}

// Let's make it a "pointed functor"

ClassList.of = function(classes) {
  return new ClassList(() => {
    return classes;
  });
};

// And is a Functor after all. It should map
ClassList.prototype.map = function(fn) {
  return ClassList.of(fn(this.getClasses()));
};

Example_usage_v1.js

const mapFn = fn => lst => lst.map(fn);
const solarize = cls => cls.concat('--solarized');
const mapSolarize = mapFn(solarize);

ClassList.of([
  'btn',
  'btn-primary',
  'btn-primary--active'
]).map(mapSolarize).getClasses();

// ['btn--solarized','btn-primary--solarized', 'btn-primary--active--solarized']