reactjs - Authenticate async with react-router-v4

Question

I have this PrivateRoute component (from the docs):

const PrivateRoute = ({ component: Component, ...rest }) => (
  <Route {...rest} render={props => (
    isAuthenticated ? (
      <Component {...props}/>
    ) : (
      <Redirect to={{
        pathname: '/login',
        state: { from: props.location }
      }}/>
    )
  )}/>
)

I would like to change isAuthenticated to an aysnc request isAuthenticated(). However, before the response has returned the page redirects.

To clarify, the isAuthenticated function is already set up.

How can I wait for the async call to complete before deciding what to display?

Answer 1

If you aren't using Redux or any other kind of state management pattern you can use the Redirect component and components state to determine if the page should render. This would include setting state to a loading state, making the async call, after the request has completed save the user, or lack of user to state and render the Redirect component, if criteria is not met the component will redirect.

class PrivateRoute extends React.Component {
  state = {
    loading: true,
    isAuthenticated: false,
  }
  componentDidMount() {
    asyncCall().then((isAuthenticated) => {
      this.setState({
        loading: false,
        isAuthenticated,
      });
    });
  }
  render() {
    const { component: Component, ...rest } = this.props;
    if (this.state.loading) {
      return <div>LOADING</div>;
    } else {
      return (
        <Route {...rest} render={props => (
          <div>
            {!this.state.isAuthenticated && <Redirect to={{ pathname: '/login', state: { from: this.props.location } }} />}
            <Component {...this.props} />
          </div>
          )}
        />
      )
    }
  }
}