store.createChangeTrigger.js

// Register a change with the actionType 'INCREMENT' and the appropriate reducer.
// This returns a change-trigger function (see below)
const increment = store.createChangeTrigger({
  actionType: 'INCREMENT',
  reducer: (state, payload, action) => {
    return state + payload.value;
  }
});

// Calling increment() will dispatch the following action:
// {type: 'INCREMENT', payload: {value: 10}}
increment({value: 10});

/*
  This will be picked up by the internal slim-redux reducer 
  which in turn will execute your previously provided reducer code:
  
  reducer: (state, payload, action) => {  
    return state + payload.value;
  }
*/