javascript - How to trigger off callback after updating state in Redux?

Question

In React, state is not be updated instantly, so we can use callback in setState(state, callback). But how to do it in Redux?

After calling the this.props.dispatch(updateState(key, value)), I need to do something with the updated state immediately.

Is there any way I can call a callback with the latest state like what I do in React?

Answer 1

component should be updated to receive new props.

there are ways to achieve your goal:

1. componentDidUpdate check if value is changed, then do something..

 componentDidUpdate(prevProps){
     if(prevProps.value !== this.props.value){ alert(prevProps.value) }
  }

2. redux-promise ( middleware will dispatch the resolved value of the promise)

export const updateState = (key, value)=>
Promise.resolve({
  type:'UPDATE_STATE',
  key, value
})

then in component

this.props.dispatch(updateState(key, value)).then(()=>{
   alert(this.props.value)
})

2. redux-thunk

export const updateState = (key, value) => dispatch => {
  dispatch({
    type: 'UPDATE_STATE',
    key,
    value,
  });
  return Promise.resolve();
};

then in component

this.props.dispatch(updateState(key, value)).then(()=>{
   alert(this.props.value)
})