pnpm-patch-package.js

pnpm-patch-package.js

/**
 * @description
 * Support patch-package in pnpm projects.
 *
 * `pnpm` can be tricky to use with patch-package. To minimize friction creating patches,
 * this script helps automate patching by using npm and a temp workspace to generate
 * patch files.
 *
 * @usage
 *  0. ensure the dependencies of interest are top level dependencies/devDependencies (no patching transitive deps)
 *  1. pnpm install, then make edits to your dependencies in your node_modules
 *  2. edit the below `relativePatchedFilenames`
 *  3. run `node <this-script>`
 *  4. preview the emitted patch
 *  5. use the emitted command to copy the patch into the project
 */
const relativePatchedFilenames = ["node_modules/foo/index.js"];

const path = require("path");
const srcProjectDirname = process.cwd();
const readLocalPkgJson = () => require(path.resolve(srcProjectDirname, "package.json"));
const patchPackageVersion = readLocalPkgJson().devDependencies["patch-package"];
const cp = require("child_process");
const log = (str) => console.log(`[pnpm-pp]`, str);
const cmd = (args, opts) => {
  log(args);
  cp.execSync(args, { ...opts, stdio: "inherit" });
};
const tempAppDirname = "/tmp/app"; // or os.tmpDir(), whatever
const cmdInPatchApp = (args, opts) => cmd(args, { ...opts, cwd: tempAppDirname });
const pkgUp = (filename) => {
  const pkgJsonDirname = path.dirname(filename);
  if (pkgJsonDirname === "/") throw new Error(`pkg not found for file`);
  const pkgJsonFilename = path.resolve(pkgJsonDirname, "package.json");
  try {
    const pkgJson = require(pkgJsonFilename);
    return pkgJson.name;
  } catch {
    return pkgUp(pkgJsonDirname);
  }
};

const pkgsToPatch = [
  ...new Set(relativePatchedFilenames.map((relative) => path.resolve(srcProjectDirname, relative)).map(pkgUp)).values(),
];

cmd(`mkdir -p ${tempAppDirname}`);
[
  `git init`,
  `echo node_modules > .gitignore`,
  `npm init -y`,
  `rm -rf patches`,
  `npm install -DE patch-package@${patchPackageVersion} ${pkgsToPatch.join(" ")}`,
  ...relativePatchedFilenames.map(
    (relative) => `cp "${path.resolve(srcProjectDirname, relative)}" "${path.resolve(tempAppDirname, relative)}"`
  ),
  ...pkgsToPatch.map((pkg) => `npx patch-package ${pkg}`),
  `ls -al patches`,
].forEach((cmd) => cmdInPatchApp(cmd));

console.log(`\n\nTo accept:\n\tcp ${tempAppDirname}/patches/* "${srcProjectDirname}/patches"`);