Redux - Remove an Item from an Array

JavaScript
1

I see the solution uses the spread operator and two slice operations. Is it possible to solve this with a filter sort of like what I am trying here.

  **Your code so far**

const immutableReducer = (state = [0,1,2,3,4,5], action) => {
switch(action.type) {
  case 'REMOVE_ITEM':
    // Don't mutate state here or the tests will fail
    return state.filter(index => {
      return state.index !== action.payload.index
    });
  default:
    return state;
}
};

const removeItem = (index) => {
return {
  type: 'REMOVE_ITEM',
  index
}
}

const store = Redux.createStore(immutableReducer);

  **Your browser information:**

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Safari/537.36

Challenge: Redux - Remove an Item from an Array

Link to the challenge:

2

Yes, but not like that.

  1. There is no index property on state

  2. The first parameter for filter is the element, not the index.

  3. The action does not have a payload property.

const numbers = [1, 2, 3, 4, 5];

const filtered = numbers.filter((_, idx) => idx !== 0);
console.log(filtered); // [2, 3, 4, 5]
3

what about using the spread operator to sort of add a set of indices? Then you could pass any index in the action, couldn’t you.

4

Not sure I understand what you mean. Can you post an example?

BTW I updated the solution thread with an example. But do try to do it yourself first.

5

The challenge also seems to suggest a solution using concat. Shouldn’t we be able to see a solution using concat?

6

It does, it is the commented-out code in the first solution. The Code Explanation part also mentions it.

I guess it might be made into a separate example but I’m not sure if that is really needed.

7

What does the underscore represent in your solution?

8

By the way. Earlier, I meant that {…state} has a set of indices, but this is an object so maybe filter can not be used with it. Or can you?

9

The filter method has a fixed parameter list (element, index, originalArray).

The index is in the second parameter list position and we have to have the first parameter to get the correct value for the second. As we do not need the element we can signify this by using an underscore _.

You can use whatever you like but _ is the convention for unused variables.

Sorry I still do not know what you mean.

10

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