Update the key names in an array of objects using the value from the first element of the array

Question

Update the key names in an array of objects using the value from the first element of the array

I am working with raw json data extracted from a .csv file:

[{
    "A": "CustomerCode",
    "B": "Country",
    "C": "CountryCode"
},
{
    "A": "C101",
    "B": "AUS",
    "C": "AUS01",
},
{
    "A": "C102",
    "B": "AUS",
    "C": "AUS02",
}]

Is there a way to remove the first element of the array and change the key names in each object within the array like this:

[{
    "CustomerCode": "C101",
    "Country": "AUS",
    "CountryCode": "AUS01",
},
{
    "CustomerCode": "C102",
    "Country": "AUS",
    "CountryCode": "AUS02",
}]

javascript arrays json ecmascript-6

Answer 1

Answer №1

To create new objects with keys from the first object in your array, you can utilize .map() in combination with Object.entries() and Object.fromEntries(). Here's how:

const arr = [{A:"CustomerCode",B:"Country",C:"CountryCode"},{A:"C101",B:"AUS",C:"AUS01"},{A:"C102",B:"AUS",C:"AUS02"}];

const prop_map = arr.shift();
const res = arr.map(o => 
  Object.fromEntries(
    Object.entries(o).map(([k, v]) => [prop_map[k], v]))
);

console.log(res);

In this code snippet, .shift() retrieves the first object from the array as a reference mapping object. The .map() function then processes each object in the array to create a new modified object. This modification is determined by what the inner function of .map() returns. Essentially, it converts the entries (key-value pair arrays [[key, value]]) of objects using another .map() method. Each key-value pair array is mapped to a new one where the key is defined by its associated value in the prop_map. Finally, Object.fromEntries() transforms this key-value pair array into an object, which becomes the final result generated by the .map() applied to the original array.

Please be aware that Object.fromEntries() may have limited browser compatibility, but a polyfill can be used if necessary.

Answer 2

To create new objects with keys from the first object in your array, you can utilize .map() in combination with Object.entries() and Object.fromEntries(). Here's how:

const arr = [{A:"CustomerCode",B:"Country",C:"CountryCode"},{A:"C101",B:"AUS",C:"AUS01"},{A:"C102",B:"AUS",C:"AUS02"}];

const prop_map = arr.shift();
const res = arr.map(o => 
  Object.fromEntries(
    Object.entries(o).map(([k, v]) => [prop_map[k], v]))
);

console.log(res);

In this code snippet, .shift() retrieves the first object from the array as a reference mapping object. The .map() function then processes each object in the array to create a new modified object. This modification is determined by what the inner function of .map() returns. Essentially, it converts the entries (key-value pair arrays [[key, value]]) of objects using another .map() method. Each key-value pair array is mapped to a new one where the key is defined by its associated value in the prop_map. Finally, Object.fromEntries() transforms this key-value pair array into an object, which becomes the final result generated by the .map() applied to the original array.

Please be aware that Object.fromEntries() may have limited browser compatibility, but a polyfill can be used if necessary.

Answer 3

Answer №2

To manipulate the array, start by removing the first element and then proceed to map over its contents.

let information = [{
    "A": "CustomerID",
    "B": "Region",
    "C": "RegionCode"
},
{
    "A": "ID101",
    "B": "USA",
    "C": "US01",
},
{
    "A": "ID102",
    "B": "USA",
    "C": "US02",
}];

// Eliminate the initial item in the array
information.shift();

let newInformation = information.map(({A, B, C}) => ({
    CustomerID: A,
    Region: B,
    RegionCode: C
}));

console.log(newInformation);

Answer 4

To manipulate the array, start by removing the first element and then proceed to map over its contents.

let information = [{
    "A": "CustomerID",
    "B": "Region",
    "C": "RegionCode"
},
{
    "A": "ID101",
    "B": "USA",
    "C": "US01",
},
{
    "A": "ID102",
    "B": "USA",
    "C": "US02",
}];

// Eliminate the initial item in the array
information.shift();

let newInformation = information.map(({A, B, C}) => ({
    CustomerID: A,
    Region: B,
    RegionCode: C
}));

console.log(newInformation);

Update the key names in an array of objects using the value from the first element of the array

Answer №1

Answer №2

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