gistfile1.js

// Which is more 'functional'?


//FIRST
render.allTags = pages.reduce(function (allTags, page) {
  page.tags.split(', ').forEach(function (tag) {
    allTags[tag] = ++allTags[tag] || 1;
  });
  return allTags;
}, {});

//SECOND
render.allTags = pages.reduce(function (allTags, page) {
  return allTags.concat(page.tags.split(', '));
}, []).reduce(function (countedTags, tag) {
  countedTags[tag] = ++countedTags[tag] || 1;
  return countedTags;
}, {});