Some packages like CLI tools and grunt tasks don't have a entry point, like `"main": "foo.js"` in package.json, resulting in them not being resolvable by `require.resolve()`. Unlike `require.resolve()`, this module also resolves packages without an entry point, returns `null` instead of throwing when the module can't be found, and resolves from `process.cwd()` instead `__dirname` by default.

Node.js is an event-based server-side JavaScript engine.