What is the proper way to access Redux store?

The best way to access your store in a component is to use the connect() function, that creates a new component that wraps around your existing one. This pattern is called Higher-Order Components, and is generally the preferred way of extending a component's functionality in React. This allows you to map state and action creators to your component, and have them passed in automatically as your store updates.

Let's take an example of <FilterLink> component using connect:

import { connect } from 'react-redux';
import { setVisibilityFilter } from '../actions';
import Link from '../components/Link';

const mapStateToProps = (state, ownProps) => ({
  active: ownProps.filter === state.visibilityFilter,
});

const mapDispatchToProps = (dispatch, ownProps) => ({
  onClick: () => dispatch(setVisibilityFilter(ownProps.filter)),
});

const FilterLink = connect(mapStateToProps, mapDispatchToProps)(Link);

export default FilterLink;

Due to it having quite a few performance optimizations and generally being less likely to cause bugs, the Redux developers almost always recommend using connect() over accessing the store directly (using context API).

class MyComponent {
  someMethod() {
    doSomethingWith(this.context.store);
  }
}