Filter redux store item array for duplicates

Question

I have following reducer:

case INIT:
  return {
    ...state,
    items: [...state.items, ...action.payload],
  };

I need somehow to check if in state.items array are items from action.payload array and do not include them in state.items. I have such a code:

[...state.items.filter(item => item !== action.payload)],

but it doesn't what I need, it doesn't work. Can somebody help me?

What data types do you reference in state.items and action.payload? Objects or primitive types? — str
– str, Commented Sep 26, 2018 at 7:47
[...state.items.filter((item) => item !== action.payload)] what array does your code return for this? — Kirill Matrosov
– Kirill Matrosov, Commented Sep 26, 2018 at 7:53

str · Accepted Answer · 2018-09-26 07:53:24Z

2

The easiest way to handle that with primitive types is using Set:

case INIT:
    return {
        ...state,
        items: [...new Set(state.items.concat(action.payload))],
    }

answered Sep 26, 2018 at 7:53

str

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Comments

Arup Rakshit · Accepted Answer · 2018-09-26 07:48:42Z

0

You should filter the payload.

case INIT:
      const { items } = state;
      const newItems = action.payload.filter(item => !items.includes(item))]
      return {
        ...state,
        items: items.concat(newItems),
      }

answered Sep 26, 2018 at 7:48

Arup Rakshit

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