You have a list of dishes. Each dish is associated with a list of ingredients used to prepare it. You want to group the dishes by ingredients, so that for each ingredient you'll be able to find all the dishes that contain it (if there are at least 2 such dishes). Return an array where each element is a list with the first element equal to the na…

groupingDishes.js

function groupingDishes(dishes) {
  const ingredientMap = dishes.reduce((map, dish) => {
    dish.slice(1).forEach((ingredient) => {
      if (!map[ingredient]) {
        map[ingredient] = [dish[0]];
      } else {
        // if happens more than once it should be an ingredient
        map[ingredient].push(dish[0]);
      }
    });
    return map;
  }, {});
  // console.log(ingredientMap);
  const results = [];
  Object.keys(ingredientMap).sort().forEach((key) => {
    if (ingredientMap[key].length >= 2) {
      results.push([key, ...ingredientMap[key].sort()])
    }
  });
  return results;
}