recursive-permutations.ts

const recursive = (input: string[][]): string[][] => {
  if (input.length === 0) return [];
  if (input.length === 1) return input[0].map((i) => [i]);

  const arr = input[0];
  const perm = recursive(input.slice(1));
  const result = arr.map((a) => perm.map((p) => [a, ...p])).flat(1);
  return result;
};

const input = [
    [
        "Small",
        "Medium",
        "Large"
    ],
    [
        "Red",
        "Green"
    ],
    [
        "50g",
        "100g",
        "250g"
    ]
]

const output = [
    [
        "Small",
        "Red",
        "50g"
    ],
    [
        "Small",
        "Red",
        "100g"
    ],
    [
        "Small",
        "Red",
        "250g"
    ],
    [
        "Small",
        "Green",
        "50g"
    ],
    [
        "Small",
        "Green",
        "100g"
    ],
    [
        "Small",
        "Green",
        "250g"
    ],
    [
        "Medium",
        "Red",
        "50g"
    ],
    [
        "Medium",
        "Red",
        "100g"
    ],
    [
        "Medium",
        "Red",
        "250g"
    ],
    [
        "Medium",
        "Green",
        "50g"
    ],
    [
        "Medium",
        "Green",
        "100g"
    ],
    [
        "Medium",
        "Green",
        "250g"
    ],
    [
        "Large",
        "Red",
        "50g"
    ],
    [
        "Large",
        "Red",
        "100g"
    ],
    [
        "Large",
        "Red",
        "250g"
    ],
    [
        "Large",
        "Green",
        "50g"
    ],
    [
        "Large",
        "Green",
        "100g"
    ],
    [
        "Large",
        "Green",
        "250g"
    ]
]