How do i update array of objects in Zustand?

Updating object arrays in Zustand is a common operation, especially when dealing with applications that have multiple state fields. Below are specific steps and code examples to demonstrate how to effectively update object arrays in Zustand.

Step 1: Create Zustand Store

First, we need to create a Zustand store to store our state, which includes an object array.

javascript
import create from 'zustand'

const useStore = create(set => ({
  items: [],
  addItem: (item) => set(state => ({ items: [...state.items, item] })),
  updateItem: (id, newItem) => set(state => ({
    items: state.items.map(item => item.id === id ? { ...item, ...newItem } : item)
  })),
  removeItem: (id) => set(state => ({
    items: state.items.filter(item => item.id !== id)
  })),
}))

Step 2: Update Objects Within the Array

Updating objects within an array in Zustand typically involves using the .map() method, which creates a new array containing the modified objects. If the object's ID matches the ID we want to update, we return a new object that merges the new properties; otherwise, we return the original object.

As shown in the updateItem method above:

javascript
updateItem: (id, newItem) => set(state => ({
  items: state.items.map(item => item.id === id ? { ...item, ...newItem } : item)
})),

Example: Using Zustand to Update Objects Within an Array

Assume we have an application that manages a to-do list. Each to-do item is an object with id and text properties. We want to update the text of a to-do item with ID 2.

javascript
// Assume initial state is as follows
useStore.setState({
  items: [
    { id: 1, text: 'Buy milk' },
    { id: 2, text: 'Read a book' }
  ]
});

// Update the to-do item with ID 2
useStore.getState().updateItem(2, { text: 'Write an essay' });

// Now the state should be:
console.log(useStore.getState().items);
// Output: [{ id: 1, text: 'Buy milk' }, { id: 2, text: 'Write an essay' }]

Through the above steps and examples, we can see that updating object arrays in Zustand is achieved by creating a new array and modifying the properties of the specified object. This approach maintains immutability of the state while ensuring the performance and maintainability of the application.