groupingDishes

answer.js

function solution(dishes) {
  let dishMap = {};
  let ingredientsMap = {};
  dishes.forEach((_, i) => {
    dishMap[dishes[i][0]] = new Set(dishes[i].slice(1));
  });
  [...new Set(dishes.map((x) => x.slice(1)).flatMap((x) => x))].map((x) => {
    for (const key in dishMap) {
      if (dishMap[key].has(x)) {
        if (ingredientsMap[x] === undefined) ingredientsMap[x] = [];
        ingredientsMap[x].push(key);
      }
    }
  });
  return Object.entries(ingredientsMap)
    .filter(([key, value]) => {
      if (value.length >= 2) {
        return [key, value.sort()];
      }
    })
    .sort((a, b) => {
      if (a[0] < b[0]) return -1;
      if (a[0] > b[0]) return 1;
      return 0;
    })
    .map((x) => x.flat());
}

My answer for CodeSignal where:

For

  dishes = [["Salad", "Tomato", "Cucumber", "Salad", "Sauce"],
            ["Pizza", "Tomato", "Sausage", "Sauce", "Dough"],
            ["Quesadilla", "Chicken", "Cheese", "Sauce"],
            ["Sandwich", "Salad", "Bread", "Tomato", "Cheese"]]
            
the output should be

  solution(dishes) = [["Cheese", "Quesadilla", "Sandwich"],
                      ["Salad", "Salad", "Sandwich"],
                      ["Sauce", "Pizza", "Quesadilla", "Salad"],
                      ["Tomato", "Pizza", "Salad", "Sandwich"]]
For

  dishes = [["Pasta", "Tomato Sauce", "Onions", "Garlic"],
            ["Chicken Curry", "Chicken", "Curry Sauce"],
            ["Fried Rice", "Rice", "Onions", "Nuts"],
            ["Salad", "Spinach", "Nuts"],
            ["Sandwich", "Cheese", "Bread"],
            ["Quesadilla", "Chicken", "Cheese"]]
            
the output should be

  solution(dishes) = [["Cheese", "Quesadilla", "Sandwich"],
                      ["Chicken", "Chicken Curry", "Quesadilla"],
                      ["Nuts", "Fried Rice", "Salad"],
                      ["Onions", "Fried Rice", "Pasta"]]