index.js

import { createStore, applyMiddleware } from 'redux';
import { actions, combineForms, getField } from 'react-redux-form';
import thunk from 'redux-thunk';

const formsReducer = combineForms({
  user: { arr: [] },
});

const store = createStore(formsReducer, applyMiddleware(thunk));

store.dispatch(actions.push('user.arr', { id: 42 }));
console.log('Before:', getField(store.getState(), 'user.arr'));
store.dispatch(actions.remove('user.arr', 0));
console.log('After:', getField(store.getState(), 'user.arr'));

package.json

{
  "name": "esnextbin-sketch",
  "version": "0.0.0",
  "dependencies": {
    "redux": "3.6.0",
    "react-redux-form": "1.11.1",
    "redux-thunk": "2.2.0",
    "babel-runtime": "6.23.0"
  }
}