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);
});

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);
});

• javascript
• arrays
• reactjs
• loops
• object

9 Answers 9

You can use the .reduce function:

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

=> 121212

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 })

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
  }

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;
}, '');

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);

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.

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.

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);

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}, '')