Learning Redux

Inserting items

Let's say, we want to insert an item at the index i. First, we create two slices:

• The beginning of the array (from 0 to i)
• The end of the array (from i)

Then, we create a new array from the first slice, our new item, and the second slice:

const insertItem = (state = [], action) => {  const i = action.index  const item = action.item  return [    ...state.slice(0, i),    item,    ...state.slice(i)  ]}