Conditional Rendering in React

Show UI only when a condition is true. Ternary when both sides exist: loggedIn ? <Home /> : <Login />. && when the false side is nothing: ok && Saved. Watch zero: {count && Mail} prints 0 when count is 0 because 0 is falsy but still a valid React child. Use count > 0 && or a ternary.

Early return is also conditional rendering: if (!user) return Sign in; then the happy path below. Don’t nest five ternaries — extract a small component.

Conditional Rendering in React — count 0 → No mail. count 3 → 3 new. Prefer ternary when zero is a real case.

Exam tip

Ternary vs &&. Mention the zero trap.

Example

// Conditional
export default function Inbox({ count }) {
  return (
    <section>
      {count > 0 ? <p>{count} new</p> : <p>No mail</p>}
    </section>
  );
}

Conditional Rendering in React — count 0 → No mail. count 3 → 3 new. Prefer ternary when zero is a real case.

Short notes

Ternary : both branches.
&& : optional UI.
Trap{count && …} showing 0.

Conditional Rendering in React

Early return is also conditional rendering: if (!user) return Sign in; then the happy path below. Don’t nest five ternaries — extract a small component.

Conditional Rendering in React — count 0 → No mail. count 3 → 3 new. Prefer ternary when zero is a real case.

Exam tip

Ternary vs &&. Mention the zero trap.

Example

// Conditional
export default function Inbox({ count }) {
  return (
    <section>
      {count > 0 ? <p>{count} new</p> : <p>No mail</p>}
    </section>
  );
}

Conditional Rendering in React — count 0 → No mail. count 3 → 3 new. Prefer ternary when zero is a real case.

Short notes

Ternary : both branches.
&& : optional UI.
Trap{count && …} showing 0.

Conditional Rendering in React

Example

Short notes

Questions

Conditional Rendering in React

Example

Short notes

Questions