Can you use Mocha to test Zustand's computed values

Example

javascript
import { create } from 'zustand';
import { expect } from 'chai';
import { sinon } from 'sinon';

describe('Computed Values', () => {
  let store;

  beforeEach(() => {
    store = create((set) => ({
      count: 0,
      increment: () => set((state) => ({ count: state.count + 1 })),
      doubleCount: computed(() => store.state.count * 2),
    }));
  });

  it('should compute doubleCount correctly', () => {
    expect(store.state.doubleCount).to.equal(0);

    store.increment();
    expect(store.state.doubleCount).to.equal(2);

    store.increment();
    expect(store.state.doubleCount).to.equal(4);
  });

  it('should compute doubleCount correctly with reset', () => {
    store.increment();
    expect(store.state.doubleCount).to.equal(2);

    store = create((set) => ({
      count: 0,
      increment: () => set((state) => ({ count: state.count + 1 })),
      doubleCount: computed(() => store.state.count * 2),
    }));

    expect(store.state.doubleCount).to.equal(0);
  });
});

Explanation

1. Create a Zustand Store: Create a Zustand store with a computed value `doubleCount` that multiplies the `count` by 2.

2. Test Computed Value: Use Mocha to test the computed value. In the first test, increment the count and verify that the `doubleCount` is updated correctly.

3. Reset Store: In the second test, reset the store and verify that the `doubleCount` is reset to its initial value.

Key Points

- Computed Values: Zustand provides a way to compute values based on the state of the store. This is useful for creating derived values that depend on other values in the store.
- Testing Computed Values: You can test computed values by verifying that they are updated correctly when the underlying state changes.
- Resetting Store: You can reset the store to its initial state by creating a new instance of the store.

By following these steps, you can effectively test Zustand's computed values using Mocha.