How correct is this implementation of adding and removing elements?

Question

JavaScript

The example has two methods: adding and removing an element from an array. In React, you can't change state directly.
In order to add an element to an array using the push method, I need to create a copy of the array because the push method is mutable.
To remove an element, I used the splice method. It's immutable, so you don't need to make a copy of the array, but since this.state.items is repeated more than once, it's not a bad idea to destructure. Why does removeItem work as a method, but addItem only as an arrow function? Me interests how correctly I implemented these two methods.

Answer 1

So you seem to be aware that the state should not be changed directly - but nevertheless you do it.
What do you mean by "mutable" and "immutable" in relation to array methods, I don't know, and I don't want to know. But I can say for sure - not what you need. You should definitely take a look here .
Make a copy of the array before splice, and splice itself on the copy - just like push when adding an element.
By the way, about the addition - why do you have a constant in the method code as a new id? Clicked "add" twice - here are two elements with the same id. Was it really that hard to generate a unique one? For example .