Manipulate the elements within an array, make changes, and then insert

Question

Manipulate the elements within an array, make changes, and then insert

In the array called newData, I am trying to add one more element with Rank 1. However, the issue is that the Rank value is getting updated for both records. The desired behavior is to have Rank set to 1 for the second record and have the first record's Rank as null.

I need help identifying what mistake I might be making in the following code.

let newData = [{
    "key1": {
        "cc":'IND'   
    },          
    "key2": {
        "rank": null
    }
}];

let setData = newData.concat(newData.slice());

setData.forEach(data => { 
    data.key2.rank =+ 1;
});

javascript typescript

Answer 1

Answer №1

One possible solution is as follows:

let newData = [{"key1": {"cc":'IND' }, "key2": {"rank": null}}];

    // To combine arrays, use the spread operator and you can leverage map instead of slice
    let setData = [...newData, ...newData.map(data => { 
        /* Objects are passed by reference, so you must break the reference
         * to create a clone of the object. */
        data = JSON.parse(JSON.stringify(data));
        data.key2.rank =+ 1; 
        return data;
    })];

console.log(setData);

Answer 2

One possible solution is as follows:

let newData = [{"key1": {"cc":'IND' }, "key2": {"rank": null}}];

    // To combine arrays, use the spread operator and you can leverage map instead of slice
    let setData = [...newData, ...newData.map(data => { 
        /* Objects are passed by reference, so you must break the reference
         * to create a clone of the object. */
        data = JSON.parse(JSON.stringify(data));
        data.key2.rank =+ 1; 
        return data;
    })];

console.log(setData);

Answer 3

Answer №2

setData.forEach(data => { 
  data.key2.rank += 1;
});

Consider changing the operator from =+ to +=

Answer 4

setData.forEach(data => { 
  data.key2.rank += 1;
});

Consider changing the operator from =+ to +=

Manipulate the elements within an array, make changes, and then insert

Answer №1

Answer №2

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