Payload in React & React Native

Question

When Redux is used to incorporate the apps state in React & React Native, why is a type required in an action creator but a payload is not required?

What purpose does an action creator serve if no payload is attached to the action?

score 0 · Accepted Answer · answered Mar 14 '17 at 23:09

Sometimes you have a reducer that does not return a new state based on a payload. An example would be an action that toggles something in the state. The reducer would just need to know that the action was fired to toggle a property. Example:

const lightSwitch = (
  state = {on: false},
  action,
) => {
  switch (action.type) {
    case TOGGLE:
      return { ...state, on: !state.on };
    default: return state;
  }
}

score 0 · Answer 2 · answered Mar 14 '17 at 23:15

One of the most popular Redux action type is for a fetching/loading indicator action. For example:

export default (state = { isFetching: false }, action) => {
  switch(action.type) {
    case START_FETCHING_POSTS:
      return { ...state, isFetching: true };
    case STOP_FETCHING_POSTS:
      return { ...state, isFetching: false };
    default:
      return state;
  }
};

In this case, the action will look like this const action = { type: START_FETCHING_POSTS }

score 0 · Answer 3 · answered Dec 04 '19 at 14:09

0

render(){
 this.props.navigation.addListener(
    'didFocus',
       payload => {
         console.log("Payload is called .....................")
        }
  );

}

answered Dec 04 '19 at 14:09

Keshav Gera

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Add some explanation, please – Alexander Ushakov Dec 04 '19 at 14:33
This method is called every-time when user come back again this screen. This method is same as in android onResume() method – Keshav Gera Dec 04 '19 at 14:38
to the answer :) – Alexander Ushakov Dec 04 '19 at 14:39

Payload in React & React Native

3 Answers3