- Animating and visualising web components to provide extra effects
- Errors in the form validation and exceptions
- Adding functionality and behavior to web pages
Details of parameter– The reduce function has five parameters as seen from the syntax, these parameters are described below.
- function(total, currentValue, index, arr): This parameter is used and run for each element in an array. Apart from this, it is also a required parameter. Further, there are four more parameters to this method:
- total: It is used for specifying the previously returned value of a function or the initialValue. It is also a required parameter.
- currentValue: It is used to specify the current value of an element and is a required parameter.
- currentIndex: It is mainly used for specifying the current element array index and is an optional parameter, which means you can either give it a value or avoid it.
- arr: It is the current array object with elements and is also an optional parameter.
- initialValue: It is the value that is to be passed to the function as a parameter which is initialValue. It is an optional parameter.
To understand this more clearly, let’s take an example that has an array and the sum of all the elements in an array is to be returned using the reduce function.
Explanation of the reduced method code
In this, as soon as the button is clicked, the function sumofArray is triggered. This function when triggered performs the code written in it. It adds up all the elements in an array and stores the result in the total variable. This sum variable is then passed to the innerHTML element where it is accessed and displayed onto the web application or the front-end.