actions-index.js

export const ADD_REPO = 'ADD_REPO';
export const addRepo = repository => ({
  type: ADD_REPO,
  repository
});

export const RATE_REPO = 'RATE_REPO';
export const rateRepo = (repository, rating) => ({
  type: RATE_REPO,
  repository,
  rating
});

error.txt

$ node js/index.js 
/Users/bryanswagerty/code/react-repo-tracker/build/js/index.js:62
        (0, _index3.default)([], actions.addRepo('TEST REPO'));
                            ^

TypeError: (0 , _index3.default) is not a function
    at Object.defineProperty.value (/Users/bryanswagerty/code/react-repo-tracker/build/js/index.js:62:22)
    at __webpack_require__ (/Users/bryanswagerty/code/react-repo-tracker/build/js/index.js:20:30)
    at /Users/bryanswagerty/code/react-repo-tracker/build/js/index.js:40:18
    at Object.<anonymous> (/Users/bryanswagerty/code/react-repo-tracker/build/js/index.js:43:10)
    at Module._compile (module.js:573:32)
    at Object.Module._extensions..js (module.js:582:10)
    at Module.load (module.js:490:32)
    at tryModuleLoad (module.js:449:12)
    at Function.Module._load (module.js:441:3)
    at Module.runMain (module.js:607:10)

index.js

// require('babel-polyfill');

import * as actions from './actions/index'
import repositoryReducer from './reducers/index'

repositoryReducer([], actions.addRepo('TEST REPO'));

reducers-index.js

import * as actions from '../actions/index';

// set initial state if nothing existings
const initialRepositoryState = [];

export const repositoryReducer = (state=initialRepositoryState, action) => {
  // check action type to proceed, create if action is ADD_REPO
  if (action.type === ADD_REPO) {
    return [...state, {
      name: action.repository,
      rating: null
    }];
  }
  // if action is RATE_REPO, then find repository matching and return new state
  else if (action.type === RATE_REPO) {
    const index = state.findIndex(repository => {
      repository.name === action.repository;
    });

    // if can't find repository in state
    if (index === -1) {
      throw new Error('Could not find repository');
    }

    // build the new state array to return
    const before = state.slice(0, index);
    const after = state.slice(index + 1);
    const newRepository = Object.assign({}, state[index], {rating: action.rating});
    return [...before, newRepository, ...after];
  }
  return state;
};