must return an object. Instead received [object Object].

hi,I’m new to this

the error message is browser.js:40 Uncaught Invariant Violation:mapStateToPropsmust return an object. Instead received [object Object]. 1.

        case 'TOGGLE_TODO':


        return  state.todos.map(function(state){
                if(state.id!==action.id){
                return  state
                };

                return {...state,completed:true}
            });

(from egghead ) this will throw the error,but I don’t know why.

But if I not using return before state.todos.map it is fine

        case 'TOGGLE_TODO':


            state.todos.map(function(state){
                if(state.id!==action.id){
                return  state
                };

                //return state.completed=true}
                return {...state,completed:true}
            });

if I change to this it will not change the store

only

        case 'TOGGLE_TODO':


            state.todos.map(function(state){
                if(state.id!==action.id){
                return  state
                };

                //return state.completed=true}
                return state.completed=true
            });

and

        case 'TOGGLE_TODO':


            state.todos.map(function(state){
                if(state.id!==action.id){
                return  state
                };

                //return state.completed=true}
                return Object.assign(state,{completed:true})
            });

can successfully update the store and no error message,but this will also change the prev state,

how can I change this code? Thanks for reply.

[gaearon]

Why are you posting the reducer code? The error says mapStateToProps returned something that isn’t a plain object. Not the reducer.

My guess is your mapStateToProps returns something like state.todos which will not work. The point of that function is to provide props to component, so it has to return an object with those props. Rather than pass state.todos you would probably want { todos: state.todos }.

If this is the case, we need to make a better error message that detects arrays. Contributions are welcome.

[EasonWang01]

thanks!