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65 lines
1.8 KiB
JavaScript

import fs from "fs";
import { join } from "path";
import { URL, fileURLToPath } from "url";
import { minify } from "terser"; // eslint-disable-line import/no-extraneous-dependencies
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 filePath = join(fileURLToPath(HELPERS_FOLDER), file);
if (!file.endsWith(".js")) {
console.error("ignoring", filePath);
continue;
}
const fileContents = await fs.promises.readFile(filePath, "utf8");
const minVersionMatch = fileContents.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 source = await minify(fileContents, {
mangle: { keep_fnames: true },
// The _typeof helper has a custom directive that we must keep
compress: { directives: false },
});
output += `\
${JSON.stringify(helperName)}: helper(
${JSON.stringify(minVersion)},
${JSON.stringify(source.code)},
),
`;
}
output += "});";
return output;
}