babel-timing

Babel timing

Measure Babel compilation time file by file, plugin by plugin. See screenshot.

Note: this tool is in version 0, any minor release might introduce breaking changes.

Installation

Can be installed both as global or local dependency.

npm i babel-timing
yarn add babel-timing

Usage

CLI

babel-timing path/to/file-1.js path/to/file-2.js
babel-timing path/to/file-*.js
babel-timing path/to/entrypoint.js --follow-imports

Node

const babelTiming = require('babel-timing').babelTiming;
babelTiming(['path/to/file.js'], options);

Options

babelConfig / --babel-config

Type: string | false
Default: false

Path to a custom babel configuration file. By default Babel will try to load any existing valid configuration file.

followImports / --follow-imports

Type: bool
Default: false

Follow imported files/modules (using babel-collect-imports) and run babel-timing against them.

Currently only relative paths are considered.

importPatterns / --import-patterns

Type: string[] (cli accepts a string containing a comma-separated list)
Default: undefined

Include/exclude import paths according to the provided patterns.

output / --output

Type: string
Default: "return" ("console" when called via CLI)
Options: "return", "console", "json"

Make babel-timing results available as:

• "return" return results' object
• "console" render results in console
• "json" save results as babel-timing-results.json

How it works

Compile files with Babel 7 and get collect compilation info through wrapPluginVisitorMethod Babel config option.

Optionally follow imports using babel-collect-imports.

Results

Compilation info are extracted into the following data structure:

type Results = {
  name: string,
  totalTime: number,
  data: {
    plugin: string,
    timePerVisit: number,
    time: number,
    visits: number,
  }[]
}[]

Notes

This tool started as an attempt of measuring the time taken by Babel while running transpiled tests or compiling applications with a bundler like Webpack.

I didn't find find a way of simply monitoring Babel while running the aforementioned tools, since I couldn't relate the wrapPluginVisitorMethod calls to the file actually being compiled.

Any further idea/contribution to get to a better Babel monitoring solution is welcome.

Manual tests :)

node cli.js __fixtures__/file-1.js
node cli.js __fixtures__/file-1.js __fixtures__/file-2.js
node cli.js __fixtures__/*.js
node cli.js __fixtures__/entry.js --follow-imports

Thanks to

• babel-minify’s timing plugin
• Facebook fbt's timing plugin
• This Stack Overflow's question/answers

Todo

• Add csv output option
• Expose wrapPluginVisitorMethod
• Provide a way to consume babel-timing from other tools like webpack, jest, rollup, etc..
• Unwrap and compile node_modules packages (absolute paths)
• Prevent nested import discovery
• Find a more stable solution for making available pending babel-collect-imports Babel v7 update
• Consider using a bundler instead of babel-collect-import

Changelog

0.1.0

Initial release