How do I update a Redux store value on a timer?

I'm playing around with a bit more of reudx and I'm trying to display a value which works. The initial state is set to 0.

My goal is to increment this value by 1 every second. To accomplish this I did something like this:

  setInterval(() => {
    dispatch(Increment());
  }, 1000);

It's not really working the way I want it to, even though it increments, it does it at an extremely fast pace.

Also, another question. Inside my reducer I would in theory like to make expressions like this:

Increment: (state) => {
      state.value + 1;
    },

But when I do this redux throws the following error:

Expected an assignment or function call and instead saw an expression

Is it not possible to make such expressions inside a redux reducer?

Solution

Firstly your function here does not have a return statement

Increment: (state) => {
  state.value + 1;
},

try to change it to

Increment: (state) => {
  return state.value + 1;
},

or use parenthesis () to instead of using {()}

Increment: (state) => (
  state.value + 1;
),

And also don't forget that reducers are pure functions .............................................................

your reducer should be something like this

const initialState = { count: 0 };
export default function reducer(state = initialState, action) {
  switch(action.type) {
     case 'INCREMENT':  
       return {         
        count: state.count + 1       
      };     
     case 'DECREMENT':       
       return {         
       count: state.count - 1       
      };     
     default:       
       return state;   
  } 
}

you should then have an action that you dispatch with a type like this

dispatch({type:'INCREMENT'})

since you already have an action helper function

it goes like this

function increment() {
   return {
   type: "INCREMENT"
  } 
};

function decrement() {
   return {
   type: "DECREMENT"
  } 
};

then you can do this

 setInterval(() => {
    dispatch(increment());
  }, 1000);