timepiece/node_modules/@babel/helpers/scripts/generate-helpers.js

120 lines
3.2 KiB
JavaScript

/* eslint-disable import/no-extraneous-dependencies */
import fs from "fs";
import { join } from "path";
import { URL, fileURLToPath } from "url";
import { minify } from "terser";
import { transformSync } from "@babel/core";
import presetTypescript from "@babel/preset-typescript";
import { gzipSync } from "zlib";
const HELPERS_FOLDER = new URL("../src/helpers", import.meta.url);
const IGNORED_FILES = new Set(["package.json"]);
export default async function generateHelpers() {
let output = `/*
* This file is auto-generated! Do not modify it directly.
* To re-generate run 'yarn gulp generate-runtime-helpers'
*/
import template from "@babel/template";
function helper(minVersion: string, source: string) {
return Object.freeze({
minVersion,
ast: () => template.program.ast(source, { preserveComments: true }),
})
}
export default Object.freeze({
`;
for (const file of (await fs.promises.readdir(HELPERS_FOLDER)).sort()) {
if (IGNORED_FILES.has(file)) continue;
if (file.startsWith(".")) continue; // ignore e.g. vim swap files
const [helperName] = file.split(".");
const isTs = file.endsWith(".ts");
const filePath = join(fileURLToPath(HELPERS_FOLDER), file);
if (!file.endsWith(".js") && !isTs) {
console.error("ignoring", filePath);
continue;
}
let code = await fs.promises.readFile(filePath, "utf8");
const minVersionMatch = code.match(
/^\s*\/\*\s*@minVersion\s+(?<minVersion>\S+)\s*\*\/\s*$/m
);
if (!minVersionMatch) {
throw new Error(`@minVersion number missing in ${filePath}`);
}
const { minVersion } = minVersionMatch.groups;
const mangleFns = code.includes("@mangleFns");
const noMangleFns = [];
code = transformSync(code, {
configFile: false,
babelrc: false,
filename: filePath,
presets: [
[
presetTypescript,
{
onlyRemoveTypeImports: true,
optimizeConstEnums: true,
},
],
],
plugins: [
/**
* @type {import("@babel/core").PluginObj}
*/
{
visitor: {
ImportDeclaration(path) {
const source = path.node.source;
source.value = source.value
.replace(/\.ts$/, "")
.replace(/^\.\//, "");
},
FunctionDeclaration(path) {
if (
mangleFns &&
path.node.leadingComments?.find(c =>
c.value.includes("@no-mangle")
)
) {
const name = path.node.id.name;
if (name) noMangleFns.push(name);
}
},
},
},
],
}).code;
code = (
await minify(code, {
ecma: 5,
mangle: {
keep_fnames: mangleFns ? new RegExp(noMangleFns.join("|")) : true,
},
// The _typeof helper has a custom directive that we must keep
compress: { directives: false, passes: 10 },
})
).code;
output += `\
// size: ${code.length}, gzip size: ${gzipSync(code).length}
${JSON.stringify(helperName)}: helper(
${JSON.stringify(minVersion)},
${JSON.stringify(code)},
),
`;
}
output += "});";
return output;
}