Remove last element of array in Redux with immutability-helper without knowing array's length

Question

I am using immutability-helper (https://github.com/kolodny/immutability-helper) to update state in Redux actions. I have an array and I'm adding an element like this:

update(state, { modalAlerts: { $push : [payload] } })

It works great. However, I don't know how to remove the last element of the array using Immutability Helper without knowing the size of the array. What is the equivalent of something like update(state, { $pop: modalAlerts } }) (it doesn't exist) to remove the last element?

Answer 1

Looking directly at the source code for immutability helper, it does not have what you are looking for. However you can extend it per the docs to add that functionality.

This then becomes a question of how to remove the last element of an array, which is already answered here with a few options including using pop, but can be as simple as:

arr.splice(-1, 1);

Since immutability helper does have a $splice command, that might enough.