interface ListOfBoxes {
  code: string
  bomb?: boolean
  boxes?: ListOfBoxes[]
}

export function findTheBomb (listOfBoxes: ListOfBoxes [], path: string[] = []): string | null {
  if (!listOfBoxes.length) {
    return "No Boxes No Bomb!"
  }
  
  
  for (const box of listOfBoxes) {
      const newPath = [...path, box.code]
      if (box.bomb) {
          return newPath.join(" > ")
      }
      if (box.boxes) {
          const found = findTheBomb(box.boxes, newPath)
          if (found) {
            return found
          }
      }
  }
  
  return null
}

const listBoxes1: ListOfBoxes [] = [
  {
    code: "B1",
    boxes: [
      {
        code: "B1.1"
      },
      {
        code: "B1.2"
      }
    ]
  },
  {
    code: "B2",
    boxes: [
      {
        code: "B2.1",
        boxes: [
          {
            code: "B2.1.1"
          },
          {
            code: "B2.1.2",
            bomb: true
          }
        ]
      },
      {
        code: "B2.2"
      }
    ]
  }
]
const listBoxes2: ListOfBoxes [] = [
  {
    "code": "B1.2",
    "boxes": [
      {
        "code": "B1.2.2",
        "boxes": [
          {
            "code": "B1.2.2.6"
          }
        ]
      },
      {
        "code": "B1.2.7"
      },
      {
        "code": "B1.2.4"
      },
      {
        "code": "B1.2.0"
      },
      {
        "code": "B1.2.9",
        "boxes": [
          {
            "code": "B1.2.9.0",
            "bomb": true,
          }
        ]
      }
    ]
  },
  {
    "code": "B2.8",
    "boxes": [
      {
        "code": "B2.8.0"
      },
      {
        "code": "B2.8.7"
      },
      {
        "code": "B2.8.6"
      },
      {
        "code": "B2.8.3"
      }
    ]
  },
  {
    "code": "B3.6",
    "boxes": [
      {
        "code": "B3.6.5"
      },
      {
        "code": "B3.6.7",
        "boxes": [
          {
            "code": "B3.6.7.9"
          }
        ]
      }
    ]
  }
]
const listBoxes3: ListOfBoxes [] = [
  {
    "code": "B1.6",
    "boxes": [
      {
        "code": "B1.6.9"
      },
      {
        "code": "B1.6.2"
      }
    ]
  },
  {
    "code": "B2.4",
    "boxes": [
      {
        "code": "B2.4.0"
      },
      {
        "code": "B2.4.3",
        "boxes": [
          {
            "code": "B2.4.3.9",
            "bomb": true
          }
        ]
      },
      {
        "code": "B2.4.7"
      }
    ]
  }
]

findTheBomb([])
findTheBomb(listBoxes1);
findTheBomb(listBoxes2);
findTheBomb(listBoxes3);