Access React Context outside of render function

EDIT: With the introduction of react-hooks in v16.8.0, you can use context in functional components by making use of useContext hook

const Users = () => {
    const contextValue = useContext(UserContext);
    // rest logic here
}

EDIT: From version 16.6.0 onwards. You can make use of context in lifecycle method using this.context like

class Users extends React.Component {
  componentDidMount() {
    let value = this.context;
    /* perform a side-effect at mount using the value of UserContext */
  }
  componentDidUpdate() {
    let value = this.context;
    /* ... */
  }
  componentWillUnmount() {
    let value = this.context;
    /* ... */
  }
  render() {
    let value = this.context;
    /* render something based on the value of UserContext */
  }
}
Users.contextType = UserContext; // This part is important to access context values

---

Prior to version 16.6.0, you could do it in the following manner

In order to use Context in your lifecyle method, you would write your component like

class Users extends React.Component {
  componentDidMount(){
    this.props.getUsers();
  }

  render(){
    const { users } = this.props;
    return(

            <h1>Users</h1>
            <ul>
              {users.map(user) => (
                <li>{user.name}</li>
              )}
            </ul>
    )
  }
}
export default props => ( <UserContext.Consumer>
        {({users, getUsers}) => {
           return <Users {...props} users={users} getUsers={getUsers} />
        }}
      </UserContext.Consumer>
)

Generally you would maintain one context in your App and it makes sense to package the above login in an HOC so as to reuse it. You can write it like

import UserContext from 'path/to/UserContext';

const withUserContext = Component => {
  return props => {
    return (
      <UserContext.Consumer>
        {({users, getUsers}) => {
          return <Component {...props} users={users} getUsers={getUsers} />;
        }}
      </UserContext.Consumer>
    );
  };
};

and then you can use it like

export default withUserContext(User);