gem-hunter
Language: JavaScript
Mad metrics for your rollup bundles, know all the things
Mad metrics for your rollup bundles, know all the things
$ npm install --save-dev rollup-plugin-analyzer
import analyze from 'rollup-plugin-analyzer'
const analyze = require('rollup-plugin-analyzer')
export default { entry: 'module.js', dest: 'index.js', format: 'cjs', plugins: [analyze()] }
rollup({ entry: 'main.js', plugins: [analyze()] }).then(...)
const limitBytes = 1e6 const onAnalysis = ({ bundleSize }) => { if (bundleSize < limitBytes) return console.log(`Bundle size exceeds ${limitBytes} bytes: ${bundleSize} bytes`) return process.exit(1) } rollup({ entry: 'main.js', plugins: [analyze({ onAnalysis, skipFormatted: true })] }).then(...)
logged to console on rollup completion
----------------------------- Rollup File Analysis ----------------------------- bundle size: 2.809 KB original size: 11.436 KB code reduction: 75.44 % module count: 5 █████████████████████████████████████████████░░░░░ file: /virtual-insanity.js bundle space: 90.64 % rendered size: 2.546 KB original size: 2.57 KB code reduction: 0.93 % dependents: 1 - /jamiroquai.js ██░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ file: /bundle-a.js bundle space: 4.27 % rendered size: 120 Bytes original size: 309 Bytes code reduction: 61.17 % dependents: 0 █░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ file: /jamiroquai.js bundle space: 2.95 % rendered size: 83 Bytes original size: 169 Bytes code reduction: 50.89 % dependents: 1 - /the-alphabet-but-incomplete.js ...
----------------------------- Rollup File Analysis ----------------------------- bundle size: 2.809 KB original size: 11.436 KB code reduction: 75.44 % module count: 5 /virtual-insanity.js █████████████████████████████████████████████░░░░░ 90.64 % (2.546 KB) /bundle-a.js ██░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ 4.27 % (120 Bytes) /jamiroquai.js █░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ 2.95 % (83 Bytes) /the-alphabet-but-incomplete.js ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ 1.17 % (33 Bytes) /the-declaration-of-independence.js ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ 0.96 % (27 Bytes)
falsenullnullfilterSummary to truemodule object specified below, should return booleanfalsetrue the filter and limit options will also remove any filtered out module data from the summaryprocess.cwd()falsefalsefalsefalsenullnull(id) => id.replace(/^\0(?:commonjs-proxy:)?/, '')nullmodule analysis objects
This module is geared towards the details of the individual modules that make up the bundle and their relative impact to bundle size. That's a detailed way of saying, it doesn't really care about size on disk. There are other options which focus on size on disk as well as delivery size which can be used alongside this module (or in place of if your concern is not per module impact). In particular rollup-plugin-size-snapshot seems like a great option for that.
Getting a bit further into the details, rather than just intent, of why the reported size differs from that on disk. We get the module data from Rollup which reports it after chunk (module) resolution and tree-shaking, but before post-processing (such as minification and compression). We then add the sizes of each of those modules together, this is the bundle size that we report.
That means it won't account for post-processing from other plugins and also won't account for post-processing by Rollup itself, which includes boilerplate / shims depending on what the output format is (CJS, ESM, iife, etc...).
Rollup allows you to output to multiple files. If you are outputting to multiple files you will get a distinct analysis for each output file. Each analysis will contain data on the files imported by the respective target.
One way to manipulate the number of reports in this scenario is through the onAnalysis callback option:
// Track iterations over output files let analyzePluginIterations = 0; export default { input: 'myIsomorphicModule.js', output: [ { name: 'myIsomorphicModule', format: 'cjs', entryFileNames: '[name].cjs' }, { name: 'myIsomorphicModule', format: 'es', entryFileNames: '[name].mjs' } ], plugins: [ analyze({ onAnalysis: () => { if (analyzePluginIterations > 0) { throw ''; // We only want reports on the first output } analyzePluginIterations++; } }) ] }
MIT © Andrew Carpenter