How To Clear an Array in JavaScript
What comes to your mind when you think of clearing an array in JavaScript? There are many methods to clear an array, from using the length property to assigning a new empty array. But depending on your requirements and other things like the system and server where the software is deployed.
For instance, if your software is on a large scale then choosing the method would be crucial because you have to take care of customers, not let the system down, and get the work done in a short time as well.
Being a JavaScript developer you should know which method has what downsides. For instance, if you want the work done quickly then assigning a new empty array is the best method. But it has a downside which is, this does not change the original array. So, if you have another variable or pointer, the original array still can be referenced and changed iganony.
Similarly, if you are going to use length property to set it to zero then original array elements will be deleted and you cannot retrieve them or access them in any way. Every Javascript developers for hire should not only know the method but also know when and where to use them.
In this article we are going to have a look at different methods used to clear arrays. The programming language used is Javascript. Even if you are not a Javascript developer, you can still use the same logic in other languages.
Replace method
Clearing an array by assigning the variable with a new empty array. Here is an example:
let arr = [‘hello’, ‘to’, ‘the’, ‘world’];
let arr2 = arr;
arr = [];
You can check if the array is empty by printing it or checking the length of the array, which if 0 the array is empty.
console.log(arr)
console.log(arr.length)
Using .length
Using “.length” an array can be cleared by setting the length to 0. However, all the elements of the array are deleted. This method is widely used but it is not the fastest method to clear an array in JavaScript. Check out the following code to understand the concept better.
let arr = [‘hello’, ‘to’, ‘the’, ‘world’];
arr.length = 0;
Length is a read/write property so when that property is set to 0 the elements are deleted.
Using .splice()
“.splice()” is a method and not property. This method returns the new array and takes two parameters, one of which is the array’s length. Here is the code:
let arr = [‘hello’, ‘to’, ‘the’, ‘world’];
arr.splice(0,arr.length);
console.log(arr)
Using .pop() and loop
“.pop()” is a generic method to remove elements from the array. But it does not remove all the elements. So, you have to write a loop which goes through each element and remove it in every loop until the length of the array is 0. Here is the code.
let arr = [‘hello’, ‘to’, ‘the’, ‘world’];
while(arr.length > 0) {
arr.pop();
}
This solution is the slowest, because if the length of the array is very long it will have to go through each element and then remove it. Which takes time in large scale applications where data is huge.
Now you can also ask these questions in an interview if you are a recruiter, and for JavaScript developers for hire, now you know how to remove elements from an array and which method is the best to use. Hire JavaScript developer from vteams remotely and start building the softwares you want instantly. Reach out to vteams to know more.
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