Merge arrays of object into single array of object

Question

I am looking for merge arrays of object into single array of object and append key of object to each key from inner object's key

I have object like

    var myObj = {
                "Details": [{
                        "car": "Audi",
                        "price": 40000,
                        "color": "blue"
                    },
                    {
                        "car": "BMW",
                        "price": 35000,
                        "color": "black"
                    }
                ],
                "Accounts": [{
                        "Total": 2000
                    },
                    {
                        "Total": 3000
                    }
                ]
            }

and Keys and objects length is not known, I want to merge it like

[
          {
            "Detailscar": "Audi",
            "Detailsprice": 40000,
            "Detailscolor": "blue",
            "AccountsTotal": 2000
          },
          {
            "Detailscar": "BMW",
            "Detailsprice": 35000,
            "Detailscolor": "black",
            "AccountsTotal": 3000
          }
        ]

I have tried with Ramda mergeAll but it is not working in my case as it only merge objects

here is what I tried

 var mergedArray = []
        R.mapObjIndexed((instance, instanceName) => {
            mergedArray.push(R.map((innerObj) => {
                var customObject = {};
                R.forEach((key) => {
                    customObject[`${instanceName}${key}`] = innerObj[key]
                }, Object.keys(innerObj))
                return customObject;
            }, instance))
        }, myObj)

I am trying add to each modified object to the mergerArray array but it adding for each iteration and finally, it is creating 2 arrays

mergedArray is still creating two different arrays with the key of the object to be appended to the properties of the object but I want it to be merged in the single array of object.

I am missing something. What should I do to resolve this issue?

Suggest some help.

@Sam I have taken back the vote but I'm not the only one who voted. So your question might get closed. This is why it is important to share effort. — Rajesh Dixit
– Rajesh Dixit, Commented Oct 5, 2017 at 14:34

Andrzej Smyk · Accepted Answer · 2017-10-05 14:12:42Z

1

Use Array.prototype.map and index as second parameter passsed to its callback to get element from Account object

const data = {
  "Details": [
    {
      "car": "Audi",
      "price": 40000,
      "color": "blue"
    },
    {
      "car": "BMW",
      "price": 35000,
      "color": "black"
    },
    {
      "car": "Porsche",
      "price": 60000,
      "color": "green"
    }

  ],
  "Accounts": [
    {
      "Total": 2000
    },
    {
      "Total": 3000
    },
    {
      "Total": 3000
    }

  ]
};

const mergeCarData = ({ Details, Accounts} = {}) => {
  return Details.length === Accounts.length ? Details.map(({ car, price, color}, idx) => ({
    Detailscar: car,
    Detailsprice: price,
    Detailscolor: color,
    AccountsTotal: Accounts[idx].Total
  })) : [];
};

console.log(mergeCarData(data));

answered Oct 5, 2017 at 14:12

Andrzej Smyk

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Comments

Rajesh Dixit · Accepted Answer · 2017-10-05 14:39:24Z

1

In plain Javascript, you could iterate the keys of the given object and iterate the arrays and build a new object out of the inner properties with a new key.

var object = { Details: [{ car: "Audi", price: 40000, color: "blue" }, { car: "BMW", price: 35000, color: "black" }], Accounts: [{ Total: 2000 }, { Total: 3000 }] },
    result = Object.keys(object).reduce(function (returnValue, parentKey) {
        object[parentKey].forEach(function (currentObj, i) {
            returnValue[i] = returnValue[i] || {};
            Object.keys(currentObj).forEach(function (childKey) {
                returnValue[i][parentKey + childKey] = currentObj[childKey];
            });
        });
        return returnValue;
    }, []);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

edited Oct 5, 2017 at 14:39

Rajesh Dixit

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answered Oct 5, 2017 at 14:31

Nina Scholz

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1 Comment

Rajesh Dixit Over a year ago

I just updated variable names so that it becomes easier to read. If you think its not required, please revert it. :-)

Scott Sauyet · Accepted Answer · 2017-10-05 14:49:23Z

1

Well, it's not pretty, but you could do something like this:

const convert = pipe(
  mapObjIndexed((val, name) => pipe(
    map(toPairs),
    map(map(([prop, propVal]) => objOf(name + prop, propVal))),
    map(mergeAll),
  )(val)),
  values,
  apply(zipWith(merge))
)

You can see this in action on the Ramda REPL.

answered Oct 5, 2017 at 14:49

Scott Sauyet

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Comments

Chris Phillips · Accepted Answer · 2017-10-05 19:56:50Z

1

Here you go, another option. I pulled a renameBy function from ramda recipe list. You can combine all the stuff on to one line if you want.

// https://github.com/ramda/ramda/wiki/Cookbook#rename-keys-of-an-object
const renameBy = R.curry((fn, obj) => R.pipe(R.toPairs, R.map(R.adjust(fn, 0)), R.fromPairs)(obj));

let convertNames = R.mapObjIndexed((value, key)=> {
    return R.map(renameBy(R.concat(key)), value)
})

let mergeUp = R.pipe(R.values, R.reduce(R.mergeDeepLeft,[]), R.values)

let convert = R.pipe(convertNames, mergeUp)
convert(myObj)

answered Oct 5, 2017 at 19:56

Chris Phillips

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