require is not defined in ES module scope — DedSec Project

Identify the module system

Node supports CommonJS and ECMAScript modules (ESM). A .mjs file, or a .js file under a package with "type": "module", uses ESM. The CommonJS require function is not available there by default.

// config.mjs
import { readFileSync } from "node:fs";
import { fileURLToPath } from "node:url";

const path = fileURLToPath(new URL("./settings.json", import.meta.url));
const text = readFileSync(path, "utf8");
const settings = JSON.parse(text);
console.log(settings.name);

Reproduce with a safe fixture

Create settings.json beside config.mjs with {"name":"offline"} and run node config.mjs. The expected output is offline. Resolving relative to import.meta.url avoids depending on the current working directory.

When CommonJS is appropriate

If the project intentionally uses CommonJS, use a .cjs file and its require syntax consistently rather than randomly renaming package.json. A dependency may offer only one module flavor; inspect its documented exports field before choosing import syntax.

Follow-up tests

Run the script from a different directory and verify that it still finds its sibling file. Delete settings.json in a scratch copy and make the CLI catch ENOENT distinctly from malformed JSON. Mixing file-relative and working-directory-relative paths is a frequent cause of confusion.

Reference: https://nodejs.org/api/esm.html

Keep module systems separate

When package.json declares "type": "module", a .js file uses ESM syntax. Replace CommonJS const fs = require("node:fs") with import * as fs from "node:fs" if the whole file is ESM. Alternatively a dedicated .cjs file remains CommonJS. Test both modes in a disposable project, including JSON imports that may have version-dependent ESM syntax. Do not mechanically replace require calls in third-party files or assume importing ESM with require is equivalent across Node versions.