• Understand the use cases for programmatic navigation
• Use the useHistory hook to perform programmatic navigation

So far, we've used a couple components from React Router to allow our users to navigate our React site: the NavLink and Link components. However, it would also be useful direct our users to another page without them needing to click a link. For example:

• After logging into the website, direct our user to the home page
• After logging out of the website, direct our user to the login page
• After creating a new item by filling out a form, direct our user to the detail page for that item

All of these actions require us to use programmatic navigation to change the browser URL, and show the user a new page in our application, without making the user click on a link.

To solve this problem, we can use another custom hook from React Router: the useHistory hook. Here's how it looks:

import { useHistory } from "react-router-dom";

function NavBar({ onLogout }) {
  const history = useHistory();

  function handleClick() {
    // logout the user
    onLogout();
    // then navigate them to the login page
    history.push("/login");
  }

  return (
    <nav>
      <button onClick={handleClick}>Logout</button>
    </nav>
  );
}

By calling history.push(), we can effectively navigate the user to a new page in response to any event in our application, not just when the user clicks a link!

For another example, here's how you could use history.push() to redirect the user after logging in:

function Login({ onLogin }) {
  const [formData, setFormData] = useState({
    username: "",
    password: "",
  });

  function handleChange(e) {
    setFormData({
      ...formData,
      [e.target.name]: e.target.value,
    });
  }

  function handleSubmit(e) {
    e.preventDefault();
    fetch("http://localhost:3001/login", {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
      },
      body: JSON.stringify(formData),
    })
      .then((r) => r.json())
      .then((user) => {
        onLogin(user);
        // after logging the user in, redirect to the home page!
        history.push("/home");
      });
  }

  return (
    <form onSubmit={handleSubmit}>
      <input
        type="text"
        name="username"
        value={formData.username}
        onChange={handleChange}
      />
      <input
        type="password"
        name="password"
        value={formData.password}
        onChange={handleChange}
      />
      <button type="submit">Login</button>
    </form>
  );
}

In addition to the useHistory hook, React Router also provides a special component for redirecting users to a new location: the Redirect component. This component is particularly useful in cases where you need to handle some conditional rendering. For example:

function Home({ isSignedIn }) {
  // if the user isn't signed in, redirect them to the login page
  if (!isSignedIn) return <Redirect to="/login" />;

  // otherwise, return the home page
  return (
    <div>
      <h1>Home!</h1>
    </div>
  );
}

React Router gives us full control over how to navigate users around our website. In general, using the <Link> and <NavLink> components to let users perform navigation by clicking links is preferred; however, there are certain scenarios when we want to navigate a user to a new page in addition to some other behavior, like submitting a form or logging out. The useHistory hook helps with theses scenarios.

• React Router Hooks
• React Router history object
• Redirect