@rnx-kit/esbuild-bundle-analyzer

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THIS TOOL IS EXPERIMENTAL — USE WITH CAUTION

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Motivation

This tool provides simple analysis of bundles based on esbuild's metafile. It allows users to analyze a bundle/metafile, compare two metafiles, and generate a limited, but compatible Webpack stats file. This file can then be used with more advanced Webpack-based analysis and comparison tools such as @mixer/webpack-bundle-compare. This tool could allow developers quickly and easily gain insights into their bundle size and composition.

Installation

yarn add @rnx-kit/esbuild-bundle-analyzer --dev

or if you're using npm

npm add --save-dev @rnx-kit/esbuild-bundle-analyzer

Usage

This tool has three commands, analyze, compare, and transform. You can find the full list of functionalities by invoking the command npx @rnx-kit/esbuild-bundle-analyzer --help.

analyze

This command will output a simple analysis of the input and output files and in-depth detail about the duplicate dependencies. This tool consumes esbuild's metafile and then analyzes the data to provide a simple analysis of the bundle. For all the duplicates the tool will present full path from the entry-point to the duplicated file to showcase why and how the duplicated files are being added in the bundle.

Generate simple analysis of a bundle by consuming esbuild's metafile:

npx @rnx-kit/esbuild-bundle-analyzer analyze <path-to-esbuild-metafile>

Along with these core options, you might want to pass the following params:

• --show-duplicates, Boolean flag to output how each duplicated file is being added to the bundle
• --json, Outputs the analysis in JSON format and sets the output file to write the analysis information to. If not set the analysis will be output to the console
• --namespace, Every module has an associated namespace. By default esbuild operates in the file namespace, which corresponds to files on the file system. @rnx-kit/metro-serializer-esbuild uses the virtual:metro namespace. This flag allows you to specify the namespace of the metafile. This is useful if you want cleaner output without the namespace prefix.

A complete example of this script is the following:

npx @rnx-kit/esbuild-bundle-analyzer analyze meta.json --json --show-duplicates --namespace virtual:metro

compare

This command will compare two metafiles and outputs the difference between the two.

npx @rnx-kit/esbuild-bundle-analyzer compare --baseline <path-to-esbuild-metafile> --candidate <path-to-esbuild-metafile>

compare

This command will compare two metafiles and outputs the difference between the two.

npx @rnx-kit/esbuild-bundle-analyzer compare --baseline <path-to-esbuild-metafile> --candidate <path-to-esbuild-metafile>

This command consumes the esbuild metafile and transforms it into a compatible Webpack stats file containing only the relevant data for @mixer/webpack-bundle-compare. Then, the Webpack stats file can be consumed by @mixer/webpack-bundle-compare which presents a visual analysis of Webpack based bundles and allows you to track and compare the bundle size over time.

Generate a webpack stats file:

npx @rnx-kit/esbuild-bundle-analyzer transform <path-to-esbuild-metafile> --output <path-to-webpack-stats-file>

Then, you can upload the generated Webpack stats file to here to visualize the bundle.