Concatenate strings within array of objects

Question

I have the array of objects as below. I want to loop through it and get Closed property values. It should be a concatenation of all the values found in each object.

For e.g. in below case, i want final result as 121212 since it has 12 in all the 3 objects.

const data = [
    {
      "personId": "1208007855",
      "details": {
        "Closed": "12"
      }
    },
    {
      "personId": "1559363884",
      "details": {
        "Closed": "12"
      }
    },
    {
      "personId": "973567318",
      "details": {
        "Closed": "12"
      }
    }
  ]

can someone let me know how to achieve this. I tried this way but couldnt succeed in achieving the result. I could only get the value of first object. Not sure how i can concatenate and store next values in this loop

There might be a situation where some objects might not have Closed property.

const totalClosed = data.forEach(function (arrayItem) {
    const x = arrayItem.details.Closed;
    console.log(x);
});

djaax · Accepted Answer · 2021-05-13 16:32:43Z

4

You can use the .reduce function:

data.reduce((accumulator, item) => accumulator += item.details.Closed, '')

=> 121212

answered May 13, 2021 at 16:32

djaax

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2 Comments

AyushKatiyar Over a year ago

what about the case when data[i].details.Closed is undefined

djaax Over a year ago

In the case that a field is undefined, you can write item.details?.Closed ?? '' instead of item.details.Closed. If item.details.Closed is null-ish, it would return an empty string: data.reduce((accumulator, item) => accumulator += item.details?.Closed ?? '', '')

Naren · Accepted Answer · 2021-05-13 17:28:21Z

2

In functional way, using reduce

const data = [
    {
        "personId": "1208007855",
        "details": {
            "Closed": "12",
            "Analyze": "10"
        }
    },
    {
        "personId": "1559363884",
        "details": {
            "Closed": "12",
            "Analyze": "10"
        }
    },
    {
        "personId": "973567318",
        "details": {
            "Closed": "12",
            "Analyze": "10"
        }
    }
]

const { Closed, Analyze } = data.reduce((acc, cur) => {
    acc.Closed += cur?.details?.Closed ?? ''
    acc.Analyze += cur?.details?.Analyze ?? ''
   return acc
}, { Closed: "", Analyze: "" })
console.log({ Closed, Analyze })

edited May 13, 2021 at 17:28

answered May 13, 2021 at 16:34

Naren

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2 Comments

Aren Trot Over a year ago

@Naren- If i have another property "Analyze" along with "Closed", how can i concatenate values of both these in single reduce ?

Naren Over a year ago

You can use object to saved all strings as a result. let me do that

ScottOverdrive · Accepted Answer · 2021-05-13 16:31:26Z

2

Try the following:

const data = [
    {
      "personId": "1208007855",
      "details": {
        "Closed": "12"
      }
    },
    {
      "personId": "1559363884",
      "details": {
        "Closed": "12"
      }
    },
    {
      "personId": "973567318",
      "details": {
        "Closed": "12"
      }
    }
  ];
  result = '';
  for (let i in data) {
      result += data[i].details.Closed
  }

answered May 13, 2021 at 16:31

ScottOverdrive

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2 Comments

AyushKatiyar Over a year ago

What about the case when data[i].details.Closed is undefined

ScottOverdrive Over a year ago

In that case use

result = '';   for (let i in data2) {       if (typeof data2[i]?.details?.Closed != 'undefined') result += data2[i]?.details?.Closed

}

Mitch Lillie · Accepted Answer · 2021-05-13 16:32:21Z

2

If you want a string and have an array, the best method is reduce:

const totalClosed = data.reduce(function (accumulator, currentVal) {
    const closed = currentVal.details.Closed || '';
    return accumulator + closed;
}, '');

answered May 13, 2021 at 16:32

Mitch Lillie

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Comments

fjplaurr · Accepted Answer · 2021-05-13 16:35:14Z

2

Using foreach exactly the same way you were trying:

const data = [
  {
    personId: '1208007855',
    details: {
      Closed: '12'
    }
  },
  {
    personId: '1559363884',
    details: {
      Closed: '12'
    }
  },
  {
    personId: '973567318',
    details: {
      Closed: '12'
    }
  }
];

let totalClosed = '';

data.forEach(function (arrayItem) {
  totalClosed = totalClosed + arrayItem.details.Closed;
});

console.log(totalClosed);

answered May 13, 2021 at 16:35

fjplaurr

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Comments

Vasi Maruseac · Accepted Answer · 2021-05-13 16:31:58Z

1

let str = "";
for(let i=0; i<data.length;i++){
str+= data[i].details.Closed;
}

console.log(str);

Also, with forEach, the elements might not be processed in the same order (0 to n) and you may find different results than you expect.

answered May 13, 2021 at 16:31

Vasi Maruseac

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Comments

beskgar · Accepted Answer · 2021-05-13 16:34:39Z

1

let str = ''
const totalClosed = data.forEach(function (arrayItem) {
  if(arrayItem.details.Closed){
        str += arrayItem.details.Closed;
  }
});

console.log(str)

You can create an empty string and add to it if the closed field exists, if there is another condition in 'Closed' you can check there in the if statement.

answered May 13, 2021 at 16:34

beskgar

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Comments

Mr. Polywhirl · Accepted Answer · 2021-05-13 16:38:37Z

1

You can reduce the data entries by destructuring the entry in the reducer and concatenating the Closed value to the running res (result). You can use the nullish-coalescing operator (??) to use an empty string instead of undefined when concatenating.

const data = [
  { "personId": "1208007855" , "details": { "Closed": "12" } },
  { "personId": "1559363884" , "details": { "Closed": "12" } },
  { "personId": "0000000000" , "details": { "Open"  : "8"  } }, // New!
  { "personId": "973567318"  , "details": { "Closed": "12" } }
];

const value = data.reduce((res, { details: { Closed } }) => res + (Closed ?? ''), '');

console.log(value);

answered May 13, 2021 at 16:38

Mr. Polywhirl

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Comments

AyushKatiyar · Accepted Answer · 2021-05-13 16:41:08Z

1

If you want to implement using loops Try Using:

const data = [
    {
      "personId": "1208007855",
      "details": {
        "Closed": "12"
      }
    },
    {
      "personId": "1559363884",
      "details": {
        "Closed": "12"
      }
    },
    {
      "personId": "973567318",
      "details": {
        "Closed": "12"
      }
    }
  ];
var res= ''
data.forEach((item)=>{if(item.details.Closed){ res += item.details.Closed;}})
console.log(res)

And this can also be done by using higher order functions: Try using :

data.reduce((res, item) =>{if(item.details.Closed)
 res += item.details.Closed;
return res}, '')

edited May 13, 2021 at 16:41

answered May 13, 2021 at 16:33

AyushKatiyar

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