Merge two array javascript

Question

I have two almost identical arrays of objects, the only difference between them is that the first array consists of inner arrays with objects having a text1 attribute, and the second array has text2 property instead. Each array contains 800 objects with same keys 1, 2, 3, 4 ....

How can I merge these two arrays? I tried with push function but got only the first array. Is there some other way to merge two arrays like reduce, filter or some other function?

let arr1 = [{
    "1": [{
        "text1": "Some text 1",
        "englishName": "Name 1",
        "number": 1,
      },
      {
        "text1": "Some text 2",
        "englishName": "Name 2",
        "number": 2,
      }
    ]
  },
  {
    "2": [{
        "text1": "Some text 3",
        "englishName": "Name 3",
        "number": 3,
      },
      {
        "text1": "Some text 4",
        "englishName": "Name 4",
        "number": 4,
      }
    ]
  }
]

let arr2 = [{
    "1": [{
        "text2": "Some new text",
        "englishName": "Name 1",
        "number": 1
      },
      {
        "text2": "Some new text 2",
        "englishName": "Name 2",
        "number": 2,
      }
    ]
  },
  {
    "2": [{
        "text2": "Some new text 3",
        "englishName": "Name 3",
        "number": 3,
      },
      {
        "text2": "Some new text 4",
        "englishName": "Name 4",
        "number": 4,
      }
    ]
  }
]

i need to merge in one array and concat text2 to first array like this

  let mergearray = [
  {
  "1": [
   {
    "text1": "Some text 1",
    "text2": "Some new text 1",
    "englishName": "Name 1",
    "number": 1,
   },
   {
    "text1": "Some text 2",
    "text2": "Some new text 2",
    "englishName": "Name 2",
    "number": 2,
  }
  ]
  },
 {
 "2": [
   {
    "text1": "Some text 3",
    "text2": "Some new text 3",
    "englishName": "Name 3",
    "number": 3,
   },
   {
    "text1": "Some text 4",
    "text2": "Some new text 4",
    "englishName": "Name 4",
    "number": 4,
   } ] } ]

How compare keys of arrays?

Can you share the desired output as well? Do you want text2 fields to be converted to text1? — Harun Yilmaz
– Harun Yilmaz, Commented Aug 28, 2019 at 9:39
i need this result let mergearray = [ { "1": [ { "text1": "Some text 1", "text2": "Some new text 1", "englishName": "Name 1", "number": 1, }, { "text1": "Some text 2", "text2": "Some new text 2", "englishName": "Name 2", "number": 2, }] } — Ismeet
– Ismeet, Commented Aug 28, 2019 at 9:47
i try with push let merge= [] for(let i=0; i<arr2.length; i++) { merged.push({ ...arr2[i], ...arr1[i] }); } — Ismeet
– Ismeet, Commented Aug 28, 2019 at 9:48

ArunPratap · Accepted Answer · 2019-08-28 10:03:17Z

1

you can use JavaScript Array concat() method the concat() method is used to join two or more arrays. This method does not change the existing arrays, it returns a new array, containing the values of the joined arrays. you can do that like this

let arr= arr1.concat(arr2); 
console.log(JSON.stringify(arr));

it will give you this result

[{"1":[{"text1":"Some text 1","englishName":"Name 1","number":1},{"text1":"Some text 2","englishName":"Name 2","number":2}]},
{"2":[{"text1":"Some text 3","englishName":"Name 3","number":3},{"text1":"Some text 4","englishName":"Name 4","number":4}]},
{"1":[{"text2":"Some new text","englishName":"Name 1","number":1},{"text2":"Some new text 2","englishName":"Name 2","number":2}]},
{"2":[{"text2":"Some new text 3","englishName":"Name 3","number":3},{"text2":"Some new text 4","englishName":"Name 4","number":4}]}]

edited Aug 28, 2019 at 10:03

answered Aug 28, 2019 at 9:46

ArunPratap

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1 Comment

Ismeet Over a year ago

i need to merge in one array and concat text2 to firt array like this let mergearray = [ { "1": [ { "text1": "Some text 1", "text2": "Some new text 1", "englishName": "Name 1", "number": 1, }, { "text1": "Some text 2", "text2": "Some new text 2", "englishName": "Name 2", "number": 2, }] } –

Akram Badah · Accepted Answer · 2019-08-28 12:33:32Z

0

Try this:

const arr3 = arr1.reduce((acc, item, index, array) => {
  if (arr2.length > index) {
    array[index][index + 1][0].text2 = arr2[index][index + 1][0].text2;
    acc = array.map((item, index2) => {
      return item[index2 + 1][0];
    });
  }
  return acc;
}, []);
console.log(JSON.stringify(arr3.reverse()))

edited Aug 28, 2019 at 12:33

answered Aug 28, 2019 at 9:42

Akram Badah

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3 Comments

Akram Badah Over a year ago

it's because I made the reduce return an object. Check the an answer again you will see that I updated it to return an array.

Ismeet Over a year ago

looks like i didn't get the desired result. I only have one in each item. I update my desired output.

Ismeet Over a year ago

this is desire uotput let mergearray = [ { "1": [ { "text1": "Some text 1", "text2": "Some new text 1", "englishName": "Name 1", "number": 1, }, { "text1": "Some text 2", "text2": "Some new text 2", "englishName": "Name 2", "number": 2, } ] }, { "2": [ { "text1": "Some text 3", "text2": "Some new text 3", "englishName": "Name 3", "number": 3, }, { "text1": "Some text 4", "text2": "Some new text 4", "englishName": "Name 4", "number": 4, } ] } ]

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