Destructive vs Non-Destructive Approach in JavaScript Arrays

JavaScript provides two approaches to adding elements to an array: destructive and non-destructive. Understanding the difference between them is crucial in developing efficient and error-free code.

Destructive Approach: The destructive approach modifies the original array using methods like push(), pop(), shift(), unshift(), etc. One example of the destructive approach is using the push() method, which adds one or more elements to the end of an array. However, this method modifies the original array, which can cause problems if you need to preserve the original array for other uses.

Example: Here is a complete running code example for the destructive approach:

Javascript

const myArray = [1, 2, 3];
myArray.push(4);

// Output: [ 1, 2, 3, 4 ]
console.log(myArray);

Output

[ 1, 2, 3, 4 ]

As you can see in the code above, we have created an array myArray with elements 1, 2, and 3. Then, we used the push() method to add element 4 to the end of the array. This method modifies the original array and adds the element to it. Finally, we have printed the modified array using console.log().

Non-Destructive Approach: The non-destructive approach creates a new array with the desired elements added to it, leaving the original array unchanged. This approach is safer and more flexible, as it allows you to preserve the original array and create new arrays with different combinations of elements.

Example: Here is a complete running code example for the non-destructive approach:

Javascript

// Using spread operator

const array = [1, 2, 3];
const newArray = [...array, 4];
console.log(array); // Output: [ 1, 2, 3 ]
console.log(newArray); // Output: [ 1, 2, 3, 4 ]

Output

[ 1, 2, 3 ]
[ 1, 2, 3, 4 ]

In the code above, we have used the spread operator (…) to create a new array newArray with all the elements of the original array and an additional element 4. This approach creates a new array without modifying the original one.

To summarize, the main difference between the destructive and non-destructive approaches is that the former modifies the original array, while the latter creates a new array leaving the original array unchanged.

Destructive Approach	Non-Destructive Approach
The Destructive approach modifies the original array or object	The non-Destructive approach does not modify the original data instead  of it creates a new array or object
It is less reusable because it modifies the data.	It is more reusable because it creates a new array or object
Destructive approaches can be more error-prone since they can modify the original data or object	Non-destructive approaches, by contrast, are less likely to introduce errors  since they leave the original data.
The destructive Approach is simple because it requires less code	The non-Destructive Approach is complex because it requires more code.