JS map generates double square brackets

Question

I use the following to merge sub-arrays:

var myArray = [
        {
            "QuestionId": 1,
            "mySeries": [{ "name": "Male", "data": [1] }],
            "mySeries1": [
                { "name": "Male", "data": [0] },
                { "name": "Female", "data": [0] },
                { "name": "Unknown", "data": [0] }
            ],
            "mySeries3": []
        },
        {
            "QuestionId": 2,
            "mySeries": [{ "name": "Banana", "data": [1] }],
            "mySeries1": [
                { "name": "Orange", "data": [0] },
                { "name": "Banana", "data": [0] },
                { "name": "None", "data": [0] }
            ],
            "mySeries3": []
        }
    ];
    var res = [];
    for (let i = 0; i < myArray.length; i++) {
        res = myArray[i].mySeries1.map(obj => myArray[i].mySeries.find(o => o.name === obj.name) || obj);
        myArray[i].mySeries3.push(res);

It works; however, I get double square brackets:

"mySeries3": **[** [
                  { "name": "Orange", "data": [0]},
                  { "name": "Banana","data": [1]},
                  {"name": "None", "data": [0] 
              ]  **]**

Is push the correct way?

You're pushing an array into an array, so of course it will. You can instead assign it to the property. `myArray[i].mySeries3 = res` or if you need to add to it you can `concat()` or use spread syntax. `myArray[i].mySeries3 = myArray[i].mySeries3.concat(res)` — pilchard, Apr 17 '22 at 00:49

score 0 · Accepted Answer · answered Apr 17 '22 at 01:03

0

I used @pilchard `

myArray[i].mySeries3 = myArray[i].mySeries3.concat(res)

It worked.`

answered Apr 17 '22 at 01:03

hncl

2,295
7
63
129

JS map generates double square brackets

1 Answers1