What is v-if?
The v-if directive is used to conditionally render elements in the DOM based on a boolean expression.
Basic Syntax
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v-else and v-else-if
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Toggle Example
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v-if vs v-show
| Feature | v-if | v-show |
|---|---|---|
| Rendering | Adds/removes from DOM | Uses CSS display |
| Performance | Slower for frequent toggles | Faster toggling |
| Initial Load | Lazy | Always rendered |
When to Use v-if
- When condition changes rarely
- When elements should not exist in DOM initially
- For conditional component rendering
Best Practices
- Use v-if for heavy components
- Use v-show for frequent toggling
- Keep conditions simple
- Avoid complex logic inside templates
Common Mistakes
- Using v-if for frequent toggling
- Complex conditions inside template
- Forgetting v-else pairing rules
- Mixing v-if with v-for improperly
Conclusion
The v-if directive is essential for conditional rendering in Vue. It allows dynamic control over the DOM and improves application flexibility.