A step towards functional fluency

const tagsReducer = (tags, name) => {
  const taggedAlready = tags.find(t => t.name === name);

  const incrementIfFound = t =>
    t === taggedAlready
      ? Object.assign(t, {count: t.count + 1})
      : t;

  return [
    ...tags.map(incrementIfFound),
    ...(taggedAlready ? [] : [{name, count: 1}]),
  ];
};

const reduce = (f, init) => as => as.reduce(f, init);
const flatten = (a, b) => [...a, ...b];
const allTags =
  compose(
    reduce(tagsReducer, []),
    reduce(flatten, []),
    map(option([])),
    map(prop('tags')),
    option([]),
    prop('clips')
  );