Typekit.js

/* @flow */
import { compose, contains, filter, forEach, flip, map, prop } from 'ramda';

type TypekitFont = {
  descriptors: {
    featureSettings: string,
    subset: string,
    unicodeRange: string,
    weight: number,
  },
  dynamic: boolean,
  family: string,
  id: number,
  source: string,
}

const kitFontToFontObject = (font: TypekitFont) => {
  return new window.Typekit.Font(font.family, font.source, font.descriptors, false);
};

const loadAllFonts = forEach(f => window.Typekit.fonts.add(f));

export function loadFonts(fonts: Array<string>) {
  const containedInFonts = compose(
    flip(contains)(fonts),
    prop('family')
  );
  if (window.Typekit) {
    compose(
      loadAllFonts,
      map(kitFontToFontObject),
      filter(containedInFonts)
    )(window.Typekit.kit);
  }
}