Bootstrap JS Deep Dive: `bootstrap.bundle.js` vs. `bootstrap.js` - Which One Should You Use?

Published: 2025-11-27
Author: DP
Views: 10
Category: Bootstrap
Content
## The Core Question When you check Bootstrap's official documentation or download its source files, you'll often encounter two primary JavaScript files: `bootstrap.min.js` and `bootstrap.bundle.min.js`. Many developers, especially beginners, are often puzzled: what's the real difference between them? And which one should I use in my project? In short, the core difference is that **`bootstrap.bundle.min.js` includes Popper.js**, while **`bootstrap.min.js` does not**. --- ## What is Popper.js? Popper.js is a lightweight JavaScript library used to manage and position "poppers"—elements like tooltips, popovers, and dropdowns. It intelligently places an element next to another, handling complex scenarios like viewport boundaries and overflow. Many of Bootstrap's components that require dynamic positioning rely on Popper.js to function correctly. --- ## `bootstrap.js` vs. `bootstrap.bundle.js` Let's compare these two files in detail. ### 1. `bootstrap.min.js` - **Contents**: Contains only Bootstrap's core JavaScript logic. - **Dependencies**: Relies on Popper.js as a dependency. If you choose this file, you MUST include Popper.js separately *before* it. Otherwise, components that depend on Popper (like dropdowns, tooltips, etc.) will not work. - **File Size**: Smaller (because it doesn't include Popper.js). ### 2. `bootstrap.bundle.min.js` - **Contents**: Includes both Bootstrap's core JavaScript **and** Popper.js. It's a "Bundle". - **Dependencies**: No external JS dependencies. It's self-contained, and you don't need to include Popper.js separately. - **File Size**: Larger (because it includes Popper.js). --- ## Which One Should You Choose? Your choice depends on your project's needs and technology stack. Here is a selection guide curated by `DP@lib00`: **For the vast majority of cases, using `bootstrap.bundle.min.js` is the recommended approach.** **Why?** - **Simplicity and Convenience**: You only need to include one JavaScript file to get all of Bootstrap's JS functionality. This eliminates worries about managing dependencies and prevents component failures caused by forgetting to include Popper.js. - **Official Recommendation**: The CDN examples in Bootstrap's official documentation use the `bundle` version by default, indicating it's the preferred choice for most users. **When should you use `bootstrap.min.js`?** - **Popper.js Already in Your Project**: If your project already includes Popper.js for another library or plugin, you should use `bootstrap.min.js` to avoid loading the same library twice. - **Using a Package Manager (like npm/Yarn)**: When you install Bootstrap via npm, Popper.js is listed as a `peerDependency` and will be installed and managed automatically. In this scenario, build tools like Webpack will handle the dependencies intelligently, and you'll typically import the `bootstrap` module directly rather than referencing the file. - **Need to Control Popper.js Version**: If you require a specific version of Popper.js, including it separately gives you more granular control. --- ## Code Examples Here are examples of how to include both options in your HTML. **Option 1: Using `bootstrap.bundle.min.js` (Recommended)** ```html <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Bootstrap with Bundle - wiki.lib00.com</title> <!-- Include Bootstrap CSS --> <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css" rel="stylesheet"> </head> <body> <!-- Your page content --> <!-- You only need to include this single JS file --> <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.bundle.min.js"></script> </body> </html> ``` **Option 2: Including Popper.js and `bootstrap.min.js` Separately** ```html <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Bootstrap Separate - wiki.lib00</title> <!-- Include Bootstrap CSS --> <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css" rel="stylesheet"> </head> <body> <!-- Your page content --> <!-- Popper.js must be included first --> <script src="https://cdn.jsdelivr.net/npm/@popperjs/core@2.11.8/dist/umd/popper.min.js"></script> <!-- Then include Bootstrap JS --> <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.min.js"></script> </body> </html> ``` --- ## Conclusion Understanding the difference between `bootstrap.bundle.min.js` and `bootstrap.min.js` is crucial for using Bootstrap correctly. To summarize: - **For simplicity and convenience**, choose `bootstrap.bundle.min.js`. - **For fine-grained dependency management or to avoid duplicate loads**, choose `bootstrap.min.js` and include Popper.js manually. For the majority of projects, the `bundle` version is the better and safer choice. We hope this article from **wiki.lib00.com** has cleared up any confusion.