Introduction

While working with Vite, adding external libraries felt like the easiest way to speed up development. Instead of building everything from scratch, I could just install a package and move on.

However, over time, I started noticing that these “quick additions” come with trade-offs. This blog captures what I learned about using external libraries in a Vite project.

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Why external libraries feel great initially

Libraries help to:

• Save development time
• Avoid reinventing common features
• Use well-tested implementations

In a fast-paced project, this is extremely useful.

For example:

• UI libraries reduce styling effort
• Utility libraries simplify logic
• Axios replaces manual fetch handling

At this stage, everything feels efficient.

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The cost: bundle size

Each library adds code to the final build.

Even if only a small part of the library is used:

• The entire module may still be included
• This increases bundle size
• Larger bundles => slower load times

This is where tree-shaking is supposed to help, but it is not always perfect.

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Tree-shaking: what-i-expected VS what-happened

Tree-shaking removes unused code during bundling.

In theory:

• Import only what you use
• Unused parts are excluded

In practice:

• Some libraries are not optimized for tree-shaking
• Incorrect imports can pull in entire modules
• Default imports are often heavier than named imports

This means performance depends not just on what you use, but how you import it.

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Dev VS Prod behavior

Vite is fast during development because:

• It uses native ES modules
• It avoids heavy bundling in dev mode

But during production:

• Everything is bundled
• Library size becomes visible
• Performance impact becomes real

So something that feels fast in development may not be efficient in production.

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When libraries become a problem

Overusing libraries can lead to:

• Increased bundle size
• Dependency conflicts
• Harder debugging
• Reduced control over logic

In some cases, writing a small custom function is simpler than importing a full library.

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What I learned

• Libraries are useful, but not always necessary
• Import style matters (named vs default)
• Production performance should be considered early
• Small, focused libraries are often better than large ones

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Conclusion

External libraries are powerful tools, but they should be used with awareness. In a Vite project, they improve development speed but can silently impact performance if not handled carefully.

Balancing convenience and efficiency is key when choosing dependencies.