How to append unwind data to the end of a CSV

[aubreyzulu]

Is there a way of appending data to the end of a CSV instead of creating a new row for the data after unwinding..? refer docs: The unwind transform deconstructs an array field from the input item to output a row for each element.

[juanjoDiaz]

I'm not sure of what you mean. Please provide an example input and the output that you would like to get in return so I can help you.

[aubreyzulu]

@juanjoDiaz

const { Parser, transforms: { unwind } } = require('json2csv');

const myCars = [
  {
    "carModel": "BMW",
    "price": 15000,
    "items": [
      {
        "name": "airbag",
        "color": "white"
      }, {
        "name": "dashboard",
        "color": "black"
      }
    ]
  }, {
    "carModel": "Porsche",
    "price": 30000,
    "items": [
      {
        "name": "airbag",
        "items": [
          {
            "position": "left",
            "color": "white"
          }, {
            "position": "right",
            "color": "gray"
          }
        ]
      }, {
        "name": "dashboard",
        "items": [
          {
            "position": "left",
            "color": "gray"
          }, {
            "position": "right",
            "color": "black"
          }
        ]
      }
    ]
  }
];

const fields = ['carModel', 'price', 'items.name', 'items.color', 'items.items.position', 'items.items.color'];
const transforms = [unwind({ paths: ['items', 'items.items'] })];
const json2csvParser = new Parser({ fields, transforms });
const csv = json2csvParser.parse(myCars);

console.log(csv);

Output

"BMW",15000,"airbag","white",,
"BMW",15000,"dashboard","black",,
"Porsche",30000,"airbag",,"left","white"
"Porsche",30000,"airbag",,"right","gray"
"Porsche",30000,"dashboard",,"left","gray"
"Porsche",30000,"dashboard",,"right","black"

**Expected Out Put**
"BMW",15000,"airbag","white",dashboard,black,
"Porsche",30000,"airbag",,"left","white,"airbag,right,gray,dashboard,left,gray,dashboard,right,black"

I don't want to repeat data for the parent object, instead, I want to append data for nested array objects

[juanjoDiaz]

You don't need unwind then. You need flatten. 🙂

const transforms = [flatten({ arrays: true })];
const json2csvParser = new Parser({ transforms });
const csv = json2csvParser.parse(myCars);

outputs

"carModel","price","items.0.name","items.0.color","items.1.name","items.1.color","items.0.items.0.position","items.0.items.0.color","items.0.items.1.position","items.0.items.1.color","items.1.items.0.position","items.1.items.0.color","items.1.items.1.position","items.1.items.1.color"
"BMW",15000,"airbag","white","dashboard","black",,,,,,,,
"Porsche",30000,"airbag",,"dashboard",,"left","white","right","gray","left","gray","right","black"

[aubreyzulu]

You don't need unwind then. You need flatten. 🙂

const transforms = [flatten({ arrays: true })];
const json2csvParser = new Parser({ transforms });
const csv = json2csvParser.parse(myCars);

outputs

"carModel","price","items.0.name","items.0.color","items.1.name","items.1.color","items.0.items.0.position","items.0.items.0.color","items.0.items.1.position","items.0.items.1.color","items.1.items.0.position","items.1.items.0.color","items.1.items.1.position","items.1.items.1.color"
"BMW",15000,"airbag","white","dashboard","black",,,,,,,,
"Porsche",30000,"airbag",,"dashboard",,"left","white","right","gray","left","gray","right","black"

@juanjoDiaz Thanks, is there a way of accessing the values (fields) dynamically?

[juanjoDiaz]

Sorry @Aubrey-Zulu I totally missed your last message.

Did you figure it out?

I do not really understand what you mean by accessing fields dynamically. If you mean having accesson function, just read the doc for the fields option