a better way if iterating an object using lodash

Question

Using lodash I'm wondering if there is a better way of doing this.

I've got an array object like below.

    {
        "ALFA ROMEO": {
            "MITO": [{
                "carData": "stuff"
            }]
        },
        "AUDI": {
            "A1": [{
                    "carData": "stuff"
                },
                {
                    "carData": "stuff"
                }
            ],
            "Q3": [{
                "carData": "stuff"
            }],
            "A3": [{
                    "carData": "stuff"
                },
                {
                    "carData": "stuff"
                },
                {
                    "carData": "stuff"
                }
            ]
        }
    }

I'm using _.forEach to iterate through the object to structure the output simular to this:

    ALFA ROMEO - 1
        MITO (1)
    AUDI - 5
        A1 (2)
        Q3 (1)
        A3 (2)

Using this I can get part way there:

        _.forEach(jData, (val, key) => {
            console.log(key)
            _.forEach(val, (val, key) => {
                console.log('    ' + key + ' (' + val.length + ')')
            })
        })

Which give me this:

    ALFA ROMEO
        MITO (1)
    AUDI
        A1 (2)
        Q3 (1)
        A3 (2)

My question is this:

a) Is there a better way of doing this without a double loop?

b) Is the only way to get a total for each make by totalling up the model counts, or is there a better way of doing this?

Thanks.

Answer 1

There's no way to do it without nested looping, since you need to print each model.

You can use _.sumBy() to get the total lengths of the models, so you can show that before the loop.

const jData = {
  "ALFA ROMEO": {
    "MITO": [{
      "carData": "stuff"
    }]
  },
  "AUDI": {
    "A1": [{
        "carData": "stuff"
      },
      {
        "carData": "stuff"
      }
    ],
    "Q3": [{
      "carData": "stuff"
    }],
    "A3": [{
        "carData": "stuff"
      },
      {
        "carData": "stuff"
      },
      {
        "carData": "stuff"
      }
    ]
  }
};

_.forEach(jData, (val, key) => {
  let total = _.sumBy(_.toArray(val), 'length');
  console.log(`${key} - ${total}`)
  _.forEach(val, (val, key) => {
    console.log(`${key} (${val.length})`)
  })
})

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