提供者react-redux中的错误

Question

When i'm run my simple program

Index.js

function test(state = []) {
    return state
}

const store = createStore(test);

render( <Provider store = { store } >
    <App / > < /Provider > ,
    document.getElementById('root')
)

App.js

const App = () => {
   return ( <h1 > Yo < /h1>)
}

export default App;

i get something like this:

Error: React.Children.only expected to receive a single React element child.
    at invariant (invariant.js:44)
    at Object.onlyChild [as only] (onlyChild.js:33)
    at Provider.render (Provider.js:49)
    at ReactCompositeComponent.js:795
    at measureLifeCyclePerf (ReactCompositeComponent.js:75)

What i'm do wrong? When i delete Provider program render App

Answer 1

This error typically occurs when you have more than one children retrieved (for example, if you render a component that has several elements but isn't wrapped in a div). Now I can't say much from looking at only the code above, try to wrap the content inside <Provider ... /> in a <div>

Answer 2

Your store should be an object, not an array. Change your test reducer to

function test(state = {}) {
    return state
}

You can store array values in your store but it needs to be an object at the top level.

{
  stuff: ['a', 'b'],
}