I am not sure of the exact syntax for a React app, but see this blog Testing Vue web applications with Vuex data store & REST backend.
Vuex is the VueJs equivalent of Redux. In summary, you add a reference to the store at some point in the app startup (code snippet is modified from the blog to be a bit more generic)
if (window.Cypress) { // only available during E2E tests window.appStore = app.store // Substitute an appropriate expression for React Redux}
and reference it in tests like so
const getStore = () => cy.window().its('appStore')it('has loading, newTodo and todos properties', () => { getStore().its('state').should('have.keys', ['loading', 'newTodo', 'todos'])})