manipulating data using javascript

Question

manipulating data using javascript

I have an array of objects like this:

var arr = [{'name':'one','age':24},{'name':'two','age':21}]

Then I assigned this array to another variable var newVar = arr. Next, I modified the value of an object in newVar using newVar[0].age = 18. However, this change also affected the original data stored in arr. The updated array became:

var arr = [{'name':'one','age':18},{'name':'two','age':21}]

I would like the original data to remain unchanged when modifying values in a different variable that holds the same data. How can I achieve this in JavaScript?

javascript arrays object

Answer 1

Answer №1

Javascript manages objects by reference. If you need to modify the value within an object, it is recommended to create a duplicate of it. This will result in two distinct objects.

Here's how you can clone an object:

Discover the most efficient method for deep cloning an object in JavaScript.

Answer 2

Javascript manages objects by reference. If you need to modify the value within an object, it is recommended to create a duplicate of it. This will result in two distinct objects.

Here's how you can clone an object:

Discover the most efficient method for deep cloning an object in JavaScript.

Answer 3

Answer №2

Make use of the new Array() method.

let array = [{'name':'John','age':30},{'name':'Jane','age':25}];
    let newArray = new Array(array);

Answer 4

Make use of the new Array() method.

let array = [{'name':'John','age':30},{'name':'Jane','age':25}];
    let newArray = new Array(array);

Answer 5

Answer №3

When it comes to copying an array, the slice method is typically used. However, it's important to note that slice only creates a shallow copy. For a deep clone, the combination of the map method and $.extend can be utilized to clone an object:

var arr = [{'name':'one','age':24},{'name':'two','age':21}]
var newArr = arr.map(function(el) {
    return $.extend({}, el);
});

newArr[0].name = 'TEST'
console.log(newArr[0].name, arr[0].name); // TEST one

An alternative method involves some JavaScript magic for a shorter implementation:

var newArr = arr.map($.extend.bind(null, {}));

The end result remains unchanged.

Answer 6

When it comes to copying an array, the slice method is typically used. However, it's important to note that slice only creates a shallow copy. For a deep clone, the combination of the map method and $.extend can be utilized to clone an object:

var arr = [{'name':'one','age':24},{'name':'two','age':21}]
var newArr = arr.map(function(el) {
    return $.extend({}, el);
});

newArr[0].name = 'TEST'
console.log(newArr[0].name, arr[0].name); // TEST one

An alternative method involves some JavaScript magic for a shorter implementation:

var newArr = arr.map($.extend.bind(null, {}));

The end result remains unchanged.

manipulating data using javascript

Answer №1

Answer №2

Answer №3

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