Does concat in JavaScript alter the original array?
In JavaScript, the `concat()` method is often used to merge two or more arrays. However, many developers are unsure about whether this method modifies the original array or creates a new one. In this article, we will explore the behavior of the `concat()` method and clarify whether it alters the original array or not.
The `concat()` method is a built-in JavaScript array method that merges two or more arrays. It does not modify the original arrays but instead returns a new array that contains the elements of the original arrays. This means that using `concat()` will not change the contents of the original arrays.
Here’s an example to illustrate this:
“`javascript
let array1 = [1, 2, 3];
let array2 = [4, 5, 6];
let result = array1.concat(array2);
console.log(result); // [1, 2, 3, 4, 5, 6]
console.log(array1); // [1, 2, 3]
console.log(array2); // [4, 5, 6]
“`
As you can see from the example, the `concat()` method merges `array1` and `array2` into a new array called `result`. The original arrays, `array1` and `array2`, remain unchanged.
It’s important to note that the `concat()` method can also be used with non-array values, such as strings or numbers. In such cases, the non-array values are converted to strings and then concatenated. However, the behavior remains the same: the original arrays are not modified.
In conclusion, the `concat()` method in JavaScript does not alter the original array. It creates a new array that contains the elements of the original arrays. This makes it a useful method for combining arrays without affecting their original contents.
