app\static\js\reducers\auth.jsx

export default (state = {}, action) => {
    switch (action.type) {
        case 'REGISTER':
            return {
                ...state,
                inProgress: false,
                errors: action.error ? action.payload.errors : null
            };
        case 'UPDATE_FIELD_AUTH':
            return {...state, [action.key]: action.value};
        case 'ASYNC_START':
            if (action.subtype === 'REGISTER') {
                return { ...state, inProgress: true };
            }
            break;
        default:
            return state;
    }
    return state;
}