How to list what transforms #babel/preset-env includes? - babeljs

Question

I like how I can use http://browserl.ist/ to see what browsers the targets query will target in #babel/preset-env.
Is there any similar tools to list what Babel plugins (transforms etc.) the env preset actually includes?
I'm using Webpack as my bundler if it matters.

Answer 1

try add debug:true in #babel/preset-env options, it will list all plugin in use
{
"presets": [
[
"#babel/preset-env",
{
"debug": true,
"targets": {
"chrome": 49,
"firefox": 64,
"safari": 9,
"edge": 13,
"ios": 9
}
}
]
]
}

Answer 2

You can always check out the source for #babel/preset-env, namely the available-plugins.js file lists the available plugins in the preset.

Answer 3

It's just a simple config in your .babelrc or babel.config.js file.
"#babel/preset-env",
{
useBuiltIns: "usage",
debug: true, // this will make babel output actual transform plugins and polyfills in terminal
targets: {
chrome: "53",
},
corejs: 3,
},
But this will not work when you use webpack

Answer 4

As pointed out by #rabidpug, available-plugins.js lists all plugins.
However, which ones are being used depend on your config.
E.g.:
The shippedProposals config option is false by default. As per index.js, this already eliminates all files as listed in data/shipped-proposals.js.
Similarly, the recently added bugfixes option adds more plugins (until babel#8 comes along), listed in #babel/compat-data/plugin-bugfixes.
Solution
Luckily, preset-env has a debug option that just prints out all plugins used when the preset is invoked.
Just add debug to your preset-env options and it will list all plugins (and more).
For convinience, I wrote this little script that independently debugs your plugins list (given a custom set of preset-env options). Run it using node list-preset-env-plugins.js in a folder where you have babel installed:
// list-preset-env-plugins.js
const babelCore = require('#babel/core');
const presetEnv = require('#babel/preset-env').default;
/**
* Your preset-env options.
* #see https://babeljs.io/docs/en/babel-preset-env#options
*/
const presetEnvOptions = {
shippedProposals: true,
debug: true
};
/**
* #see https://github.com/babel/babel/blob/master/packages/babel-helper-plugin-utils/src/index.js
*/
const apiStub = {
version: babelCore.version,
assertVersion() { }
};
// invoke the preset
presetEnv(apiStub, presetEnvOptions);