React · Theory

Conditional CSS in React

Theory

82/94

Conditional CSS in React

Toggle classes from state: className={ok ? 'alert ok' : 'alert bad'}. Or template strings: `btn ${active ? 'btn-on' : ''}`. Libraries: clsx, classnames. Prefer classes over swapping ten inline colors — CSS can animate and theme them.

Conditional CSS in React — ok false → alert bad + Failed. Class changes with state.

Exam tip

className ternary from state.

Example

// Conditional CSS
export default function Alert({ ok }) {
  return <p className={ok ? "alert ok" : "alert bad"}>{ok ? "Saved" : "Failed"}</p>;
}

Conditional CSS in React — ok false → alert bad + Failed. Class changes with state.

Short notes

DefTernary className.
RuleOr clsx().
RememberPrefer classes over inline rainbows.

React · Theory

Conditional CSS in React

← All stacks

Theory

82/94

Conditional CSS in React

Conditional CSS in React — ok false → alert bad + Failed. Class changes with state.

Exam tip

className ternary from state.

Example

// Conditional CSS
export default function Alert({ ok }) {
  return <p className={ok ? "alert ok" : "alert bad"}>{ok ? "Saved" : "Failed"}</p>;
}

Conditional CSS in React — ok false → alert bad + Failed. Class changes with state.

Short notes

DefTernary className.
RuleOr clsx().
RememberPrefer classes over inline rainbows.

Conditional CSS in React

Example

Short notes

Questions

Conditional CSS in React

Example

Short notes

Questions