frontend/build-scripts/list-plugins-and-polyfills.js

84 lines
2.9 KiB
JavaScript
Executable File

#!/usr/bin/env node
// Script to print Babel plugins and Core JS polyfills that will be used by browserslist environments
import { version as babelVersion } from "@babel/core";
import presetEnv from "@babel/preset-env";
import compilationTargets from "@babel/helper-compilation-targets";
import coreJSCompat from "core-js-compat";
import { logPlugin } from "@babel/preset-env/lib/debug.js";
// eslint-disable-next-line import/no-relative-packages
import shippedPolyfills from "../node_modules/babel-plugin-polyfill-corejs3/lib/shipped-proposals.js";
import { babelOptions } from "./bundle.cjs";
const detailsOpen = (heading) =>
`<details>\n<summary><h4>${heading}</h4></summary>\n`;
const detailsClose = "</details>\n";
const dummyAPI = {
version: babelVersion,
assertVersion: () => {},
caller: (callback) =>
callback({
name: "Dummy Bundler",
supportsStaticESM: true,
supportsDynamicImport: true,
supportsTopLevelAwait: true,
supportsExportNamespaceFrom: true,
}),
targets: () => ({}),
};
// Generate filter function based on proposal/method inputs
// Copied and adapted from babel-plugin-polyfill-corejs3/esm/index.mjs
const polyfillFilter = (method, proposals, shippedProposals) => (name) => {
if (proposals || method === "entry-global") return true;
if (shippedProposals && shippedPolyfills.default.has(name)) {
return true;
}
if (name.startsWith("esnext.")) {
const esName = `es.${name.slice(7)}`;
// If its imaginative esName is not in latest compat data, it means the proposal is not stage 4
return esName in coreJSCompat.data;
}
return true;
};
// Log the plugins and polyfills for each build environment
for (const buildType of ["Modern", "Legacy"]) {
const browserslistEnv = buildType.toLowerCase();
const babelOpts = babelOptions({ latestBuild: browserslistEnv === "modern" });
const presetEnvOpts = babelOpts.presets[0][1];
// Invoking preset-env in debug mode will log the included plugins
console.log(detailsOpen(`${buildType} Build Babel Plugins`));
presetEnv.default(dummyAPI, {
...presetEnvOpts,
browserslistEnv,
debug: true,
});
console.log(detailsClose);
// Manually log the Core-JS polyfills using the same technique
if (presetEnvOpts.useBuiltIns) {
console.log(detailsOpen(`${buildType} Build Core-JS Polyfills`));
const targets = compilationTargets.default(babelOpts?.targets, {
browserslistEnv,
});
const polyfillList = coreJSCompat({ targets }).list.filter(
polyfillFilter(
`${presetEnvOpts.useBuiltIns}-global`,
presetEnvOpts?.corejs?.proposals,
presetEnvOpts?.shippedProposals
)
);
console.log(
"The following %i polyfills may be injected by Babel:\n",
polyfillList.length
);
for (const polyfill of polyfillList) {
logPlugin(polyfill, targets, coreJSCompat.data);
}
console.log(detailsClose);
}
}