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conditional-render

Conditional rendering

Last reviewed May 28, 2026 Content v20260528
Track mode
client_react
Means
In-browser React TSX
Reading
~1 min
Level
intermediate

This lesson

This lesson teaches Conditional rendering: the concepts, APIs, and habits you need before advancing in React.

Without Conditional rendering, you will struggle to read or extend React codebases and playground exercises.

You will apply Conditional rendering in contexts like: SPAs, dashboards, design-system-driven products, and React Native mobile apps.

Write TypeScript/TSX, click Run in browser—React 18 loads from CDN, JSX compiles in the tab, UI renders in the preview root, and printOutput feeds the terminal.

When you can explain the previous lesson's ideas without copying starter code.

React has no special template syntax—use JavaScript conditionals inside JSX.

Common patterns

  • Ternary{isLoggedIn ? <Dashboard /> : <Login />}
  • Logical AND{error && <p>{error}</p>} (beware 0 rendering!)
  • Early return — guard clauses before the main JSX in a component
  • Variable assignment — compute let content = ... then return it

Keep conditions readable

Deeply nested ternaries hurt readability. Extract subcomponents or use a small helper function when branches grow.

Self-check

  1. When does {count && <Badge />} show 0 on screen?
  2. When is early return preferable to a ternary in JSX?

Challenge

Loading gate

  1. Add a loading boolean prop to Status.
  2. Show “Loading…” when true, otherwise show the message.

Done when: toggling loading switches between spinner text and the message.

Interview tip Lesson completion confidence

Can you explain this lesson in 30 seconds without reading notes?

Not saved yet.

Playground

Runs in your browser in a sandboxed frame. Backend runners appear when this track’s profile allows them.

Check yourself

Multiple choice — immediate feedback.

Discussion

Past discussion is visible to everyone. Only logged-in users can post comments and replies.

Starter discussion topics

  • && vs ternary—when?
  • Null render case?

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