group ingredients by stemmed_title

groups.js

function group_or_item(values){
  return (values.length > 1 ? 'group' : 'item');
}

function get_group_values(key) {
  return groups[key];
}

function getFrom(list) {
  return function(key) {
    return list[key];
  }
}

function groupItems(callback) {
  var _items = [{"title":"Yellow Onion","stemmed_title":"onion"},{"title":"Sweet Onion","stemmed_title":"onion"},{"title":"Red Onion","stemmed_title":"onion"},{"title":"Olive Onion","stemmed_title":"oil"},{"title":"Canola Onion","stemmed_title":"oil"},{"title":"Flour","stemmed_title":"flour"},{"title":"Water","stemmed_title":"water"},{"title":"Salt","stemmed_title":"salt"}]

  _.reduce(_.reduce(_items, function(memo, value) {
    var stemmed_title = value.stemmed_title;
    memo[stemmed_title] = memo[stemmed_title] || [];
    memo[stemmed_title].push(value);
    return memo;
  }, {}), function(memo, values, stemmed_title) {
    memo['groups'] || (memo['groups'] = {})
    memo['items'] || (memo['items'] = [])
    if (values.length > 1 ) {
      memo.groups[stemmed_title] = values;
    } else {
      memo.items.push(_.first(values));
    }
    return memo;
  }, {});

  /*
    {
       "groups":{
          "onion":[
             {
                "title":"Yellow Onion",
                "stemmed_title":"onion"
             },
             {
                "title":"Sweet Onion",
                "stemmed_title":"onion"
             },
             {
                "title":"Red Onion",
                "stemmed_title":"onion"
             }
          ],
          "oil":[
             {
                "title":"Olive Onion",
                "stemmed_title":"oil"
             },
             {
                "title":"Canola Onion",
                "stemmed_title":"oil"
             }
          ]
       },
       "items":[
          {
             "title":"Flour",
             "stemmed_title":"flour"
          },
          {
             "title":"Water",
             "stemmed_title":"water"
          },
          {
             "title":"Salt",
             "stemmed_title":"salt"
          }
       ]
    }
  */

  var groups = _.groupBy(_items, 'stemmed_title');
  var partitioned_groups = _.groupBy(_.keys(groups), _.flow(get_group_values, group_or_item))

  var groupGroups = _.reduce(partitioned_groups.group, function(memo, key){
    memo[key] = groups[key];
    return memo;
  }, {})

  var itemItems = _.flatten(_.map(partitioned_groups.item, getFrom(groups)));

  /*
  {
    "partitioned_groups": {
      "group": ["onion","oil"],
      "item": ["flour","water","salt"]
    },
    "itemItems": [
      {
        "title": "Flour",
        "stemmed_title": "flour"
      },
      {
        "title": "Water",
        "stemmed_title": "water"
      },
      {
        "title": "Salt",
        "stemmed_title": "salt"
      }
    ],
    "groupGroups": {
      "onion": [
        {
          "title": "Yellow Onion",
          "stemmed_title": "onion"
        },
        {
          "title": "Sweet Onion",
          "stemmed_title": "onion"
        },
        {
          "title": "Red Onion",
          "stemmed_title": "onion"
        }
      ],
      "oil": [
        {
          "title": "Olive Onion",
          "stemmed_title": "oil"
        },
        {
          "title": "Canola Onion",
          "stemmed_title": "oil"
        }
      ]
    }
  }
  */

  callback({partitioned_groups, groupGroups, itemItems}, arguments);
}

document.addEventListener('click', _.partial(groupItems, console.log.bind(console)));