Bundle Package Size Analyzer

Create a Rollup plugin that analyzes bundle composition and reports which packages contribute to the bundle size. The plugin should aggregate module sizes by their package name and display a sorted breakdown showing each package's contribution to the total bundle size.

Requirements

1. Plugin Implementation

   • Export a function that returns a Rollup plugin object
   • The plugin should hook into the appropriate Rollup build phase to access bundle information
   • Name the plugin appropriately

2. Package Categorization

   • Identify which modules come from npm packages (node_modules)
   • Group application code under a category called "app"
   • Handle Rollup's internal helper code appropriately

3. Size Aggregation

   • Calculate the total size of all modules belonging to each package
   • Aggregate sizes by summing all files from the same package
   • Track the overall total bundle size

4. Output Report

   • Display results to the console showing each package name and its size
   • Include percentage of total bundle size for each package
   • Sort packages by size in descending order (largest first)
   • Format sizes in a human-readable way (e.g., KB, MB)

Dependencies { .dependencies }

rollup-plugin-sizes { .dependency }

A Rollup plugin for analyzing and reporting bundle size composition by package.

rollup { .dependency }

Module bundler for JavaScript applications.

Test Cases

Test 1: Single Entry Bundle @test

Input: Rollup configuration with a single entry point that imports multiple npm packages and local application files.

Expected Output:

• Console output showing a size breakdown with package names
• Each package listed with its size and percentage
• Packages sorted from largest to smallest
• Total bundle size displayed

Test 2: Multi-Entry Bundle @test

Input: Rollup configuration with multiple entry points (array format).

Expected Output:

• Separate size reports for each bundle
• Each report showing package breakdown specific to that bundle
• Correct sizes and percentages for each entry point's dependencies