test-repo/scripts/prepare-test-for-legacy-nodejs.js

import fs from "node:fs";

const packageJsonFile = new URL("../package.json", import.meta.url);
const packageJson = JSON.parse(fs.readFileSync(packageJsonFile));

const argv = process.argv.slice(2);
const nodeVersion = Number(argv[1]);

if (argv[0] !== "--node-version" || !Number.isInteger(nodeVersion)) {
  throw new Error("Expect `--node-version` argument.");
}

let jestVersion;

if (nodeVersion === 14) {
  // `jest@30.0.0-alpha.2` is the last version that supports Node.js v14
  jestVersion = "30.0.0-alpha.2";
} else if (nodeVersion === 16) {
  // `jest@30.0.0-alpha.7` is the last version that supports Node.js v16
  jestVersion = "30.0.0-alpha.7";
} else {
  throw new Error("Unexpected `--node-version`.");
}

/*
Script to get dependencies

```js
console.log(
  Array.from(
    fs
      .readFileSync("./yarn.lock", "utf8")
      .matchAll(/"(.*?)@npm:30\.0\.0-alpha\.3[",]/g),
    (match) => match[1],
  ).sort(),
);
```
*/

const jestDependencies = [
  "@jest/console",
  "@jest/core",
  "@jest/environment",
  "@jest/expect",
  "@jest/expect-utils",
  "@jest/fake-timers",
  "@jest/globals",
  "@jest/reporters",
  "@jest/schemas",
  "@jest/source-map",
  "@jest/test-result",
  "@jest/test-sequencer",
  "@jest/transform",
  // "@jest/types",
  "babel-jest",
  "babel-plugin-jest-hoist",
  "babel-preset-jest",
  "diff-sequences",
  "expect",
  "jest",
  "jest-changed-files",
  "jest-circus",
  "jest-cli",
  "jest-config",
  "jest-diff",
  // "jest-docblock",
  "jest-each",
  "jest-environment-node",
  "jest-get-type",
  "jest-haste-map",
  "jest-leak-detector",
  "jest-matcher-utils",
  "jest-message-util",
  "jest-mock",
  "jest-regex-util",
  "jest-resolve",
  "jest-resolve-dependencies",
  "jest-runner",
  "jest-runtime",
  "jest-snapshot",
  "jest-util",
  "jest-validate",
  "jest-watcher",
  "jest-worker",
  "pretty-format",
];

const content = JSON.stringify(
  {
    ...packageJson,
    resolutions: {
      ...packageJson.resolutions,
      ...Object.fromEntries(
        jestDependencies.map((name) => [name, jestVersion]),
      ),
    },
  },
  undefined,
  2,
);

fs.writeFileSync(packageJsonFile, content);