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NextJSframework~20 mins

Font optimization with next/font in NextJS - Practice Problems & Coding Challenges

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Challenge - 5 Problems
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Font Optimization Master
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Test your skills under time pressure!
❓ component_behavior
intermediate
2:00remaining
What is the rendered font style when using next/font with Google Fonts?

Consider this Next.js component using next/font/google to load the Roboto font:

import { Roboto } from 'next/font/google';

const roboto = Roboto({ subsets: ['latin'], weight: '400' });

export default function Home() {
  return <main className={roboto.className}>Hello World</main>;
}

What font style will the text inside <main> have?

NextJS
import { Roboto } from 'next/font/google';

const roboto = Roboto({ subsets: ['latin'], weight: '400' });

export default function Home() {
  return <main className={roboto.className}>Hello World</main>;
}
AThe text will use Roboto but with bold weight because weight '400' is ignored.
BThe text will use the default system font because next/font/google does not load fonts automatically.
CThe text will use the Roboto font with normal weight and latin subset loaded.
DThe text will not render because the className is undefined.
Attempts:
2 left
💡 Hint

Check how the Roboto function from next/font/google is used and what the className property does.

📝 Syntax
intermediate
2:00remaining
Which next/font/google import syntax is correct for loading multiple weights?

You want to load the Inter font with weights 400 and 700 using next/font/google. Which import and usage syntax is correct?

A
import { Inter } from 'next/font/google';
const inter = Inter({ weight: ['400', '700'], subsets: ['latin'] });
B
import Inter from 'next/font/google';
const inter = Inter({ weight: '400,700', subsets: ['latin'] });
C
import { Inter } from 'next/font/google';
const inter = Inter({ weights: ['400', '700'], subsets: ['latin'] });
D
import { Inter } from 'next/font/google';
const inter = Inter({ weight: 400 || 700, subsets: ['latin'] });
Attempts:
2 left
💡 Hint

Check the property name and value type for specifying multiple weights in the font options.

🔧 Debug
advanced
2:00remaining
Why does this next/font/local font fail to apply styles?

Given this code snippet using next/font/local:

import localFont from 'next/font/local';

const myFont = localFont({
  src: './fonts/MyFont.woff2',
  weight: '400',
  style: 'normal'
});

export default function Page() {
  return <div className={myFont.className}>Test Text</div>;
}

The font styles do not apply in the browser. What is the most likely cause?

NextJS
import localFont from 'next/font/local';

const myFont = localFont({
  src: './fonts/MyFont.woff2',
  weight: '400',
  style: 'normal'
});

export default function Page() {
  return <div className={myFont.className}>Test Text</div>;
}
AThe className property is not available on the object returned by localFont.
BThe weight property must be a number, not a string.
CThe localFont function requires an array for the src property, not a string.
DThe relative path './fonts/MyFont.woff2' is incorrect or the file is missing.
Attempts:
2 left
💡 Hint

Check the file path and existence of the font file relative to the component.

❓ state_output
advanced
2:00remaining
What is the effect of using next/font with variable fonts on page size?

You use a variable font with next/font/google like this:

import { Roboto_Flex } from 'next/font/google';

const robotoFlex = Roboto_Flex({ subsets: ['latin'] });

export default function Home() {
  return <main className={robotoFlex.className}>Hello</main>;
}

What is the expected effect on the page size and font loading compared to loading multiple static weights?

NextJS
import { Roboto_Flex } from 'next/font/google';

const robotoFlex = Roboto_Flex({ subsets: ['latin'] });

export default function Home() {
  return <main className={robotoFlex.className}>Hello</main>;
}
AThe page size is larger because variable fonts include all weights and styles by default.
BThe page size is smaller because the variable font loads once and covers many weights and styles.
CThe page size is the same as loading a single static weight font.
DThe font does not load because variable fonts are not supported by next/font.
Attempts:
2 left
💡 Hint

Think about how variable fonts bundle multiple styles in one file.

🧠 Conceptual
expert
3:00remaining
How does next/font optimize font loading for accessibility and performance?

Which of the following best describes how next/font improves font loading in Next.js apps?

AIt automatically inlines critical font CSS, preloads fonts, and avoids layout shifts by applying font classes at build time.
BIt loads fonts only on user interaction to reduce initial load time but may cause layout shifts.
CIt bundles all font files into JavaScript to reduce HTTP requests but increases JS size.
DIt disables font loading on slow connections to improve accessibility.
Attempts:
2 left
💡 Hint

Consider how next/font handles font CSS and rendering to improve user experience.

Practice

(1/5)
1. What is the main purpose of using next/font in a Next.js application?
easy
A. To convert fonts into images for display
B. To create custom font files from scratch
C. To optimize font loading for better performance and user experience
D. To disable all fonts and use system defaults only

Solution

  1. Step 1: Understand the role of next/font

    next/font is designed to load fonts efficiently in Next.js apps, improving speed and user experience.
  2. Step 2: Compare options with this purpose

    Only To optimize font loading for better performance and user experience describes optimization of font loading, which matches the purpose of next/font.
  3. Final Answer:

    To optimize font loading for better performance and user experience -> Option C
  4. Quick Check:

    Font optimization = To optimize font loading for better performance and user experience [OK]
Hint: Remember: next/font improves font loading speed [OK]
Common Mistakes:
  • Thinking next/font creates fonts
  • Confusing font optimization with image conversion
  • Assuming next/font disables fonts
2. Which of the following is the correct way to import the Inter font from Google Fonts using next/font/google?
easy
A. import Inter from 'next/font/google'; const inter = new Inter();
B. import { Inter } from 'next/font/google'; const inter = Inter({ subsets: ['latin'] });
C. const inter = require('next/font/google').Inter();
D. import { Inter } from 'next/font/local'; const inter = Inter();

Solution

  1. Step 1: Check the import syntax for Google Fonts

    The correct import uses named import from 'next/font/google' and calls the font function with options.
  2. Step 2: Validate the usage

    import { Inter } from 'next/font/google'; const inter = Inter({ subsets: ['latin'] }); matches the correct pattern: import with braces, call with options object.
  3. Final Answer:

    import { Inter } from 'next/font/google'; const inter = Inter({ subsets: ['latin'] }); -> Option B
  4. Quick Check:

    Correct import and call = import { Inter } from 'next/font/google'; const inter = Inter({ subsets: ['latin'] }); [OK]
Hint: Use named import and call font as a function with options [OK]
Common Mistakes:
  • Using default import instead of named import
  • Using require instead of import
  • Importing from 'next/font/local' for Google Fonts
3. Given this code snippet in a Next.js component:
import { Inter } from 'next/font/google';
const inter = Inter({ subsets: ['latin'] });

export default function Home() {
  return <main className={inter.className}>Hello World</main>;
}

What will be the effect of using inter.className in the <main> element?
medium
A. It adds a random CSS class unrelated to fonts
B. It causes a runtime error because className is undefined
C. It applies default system fonts ignoring Inter
D. It applies the Inter font styles optimized and loaded by next/font

Solution

  1. Step 1: Understand what inter.className provides

    The Inter font function returns an object with a className property that applies the optimized font styles.
  2. Step 2: Check usage in the component

    Using className={inter.className} applies the Inter font styles to the <main> element.
  3. Final Answer:

    It applies the Inter font styles optimized and loaded by next/font -> Option D
  4. Quick Check:

    inter.className applies optimized font styles = It applies the Inter font styles optimized and loaded by next/font [OK]
Hint: className from next/font applies the font styles [OK]
Common Mistakes:
  • Assuming className is undefined
  • Thinking it applies system fonts instead
  • Confusing className with inline styles
4. Identify the error in this code snippet that tries to load a local font with next/font/local:
import localFont from 'next/font/local';

const myFont = localFont({
  src: './fonts/MyFont.ttf',
  weight: '400',
  style: 'normal'
});

export default function Page() {
  return <div className={myFont.className}>Sample Text</div>;
}
medium
A. The src path must be an array, not a string
B. The weight property should be a number, not a string
C. The import should use braces: { localFont }
D. The style property is not supported in local fonts

Solution

  1. Step 1: Check the src property format for localFont

    Local fonts require src to be an array of objects with path and weight, not a single string.
  2. Step 2: Validate other properties

    Weight can be string or number, import default is correct, style is supported.
  3. Final Answer:

    The src path must be an array, not a string -> Option A
  4. Quick Check:

    Local font src requires array = The src path must be an array, not a string [OK]
Hint: Local font src must be an array of objects [OK]
Common Mistakes:
  • Using string instead of array for src
  • Misusing import syntax with braces
  • Assuming style is unsupported
5. You want to load two Google Fonts, Roboto and Open Sans, both with latin subsets, and apply them to different parts of your Next.js page. Which approach correctly uses next/font/google to optimize both fonts and apply them separately?
hard
A. import { Roboto, Open_Sans } from 'next/font/google'; const roboto = Roboto({ subsets: ['latin'] }); const openSans = Open_Sans({ subsets: ['latin'] }); export default function Page() { return <> <header className={roboto.className}>Header Text</header> <main className={openSans.className}>Main Text</main> </>; }
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C. import Roboto from 'next/font/google'; import OpenSans from 'next/font/google'; const roboto = Roboto({ subsets: ['latin'] }); const openSans = OpenSans({ subsets: ['latin'] }); export default function Page() { return <> <header className={roboto.className}>Header Text</header> <main className={openSans.className}>Main Text</main> </>; }
D. import { Roboto, OpenSans } from 'next/font/google'; const roboto = Roboto({ subsets: ['latin'] }); const openSans = OpenSans({ subsets: ['latin'] }); export default function Page() { return <div className={`${roboto.className} ${openSans.className}`}>Combined Text</div>; }

Solution

  1. Step 1: Check correct font names and import syntax

    Font names must match exact exported names from next/font/google. 'OpenSans' is correct, 'Open_Sans' is not.
  2. Step 2: Verify usage of separate classNames

    Applying separate classNames to different elements is correct for different fonts.
  3. Step 3: Review other options

    import { Roboto, Open_Sans } from 'next/font/google'; const roboto = Roboto({ subsets: ['latin'] }); const openSans = Open_Sans({ subsets: ['latin'] }); export default function Page() { return <> <header className={roboto.className}>Header Text</header> <main className={openSans.className}>Main Text</main> </>; } uses wrong font name 'Open_Sans'. import Roboto from 'next/font/google'; import OpenSans from 'next/font/google'; const roboto = Roboto({ subsets: ['latin'] }); const openSans = OpenSans({ subsets: ['latin'] }); export default function Page() { return <> <header className={roboto.className}>Header Text</header> <main className={openSans.className}>Main Text</main> </>; } uses default imports incorrectly. import { Roboto, OpenSans } from 'next/font/google'; const roboto = Roboto({ subsets: ['latin'] }); const openSans = OpenSans({ subsets: ['latin'] }); export default function Page() { return <div className={`${roboto.className} ${openSans.className}`}>Combined Text</div>; } combines both fonts on one element, not separately.
  4. Final Answer:

    Use named imports with correct font names and apply classNames separately -> Option A
  5. Quick Check:

    Correct font names and separate usage = import { Roboto, OpenSans } from 'next/font/google'; const roboto = Roboto({ subsets: ['latin'] }); const openSans = OpenSans({ subsets: ['latin'] }); export default function Page() { return <> <header className={roboto.className}>Header Text</header> <main className={openSans.className}>Main Text</main> </>; } [OK]
Hint: Use exact font names and apply className separately [OK]
Common Mistakes:
  • Using incorrect font names with underscores
  • Using default imports instead of named imports
  • Combining multiple fonts on one element incorrectly
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