What are ES Modules and why are they important for avoiding `exports is not defined` errors?

ES Modules (using `import` and `export`) provide a more standardized and robust way to manage modules in JavaScript. They avoid the complexities and potential pitfalls of CommonJS `require` and `exports`. Using `export` statements clearly defines what's exposed from a module, reducing the chances of accidental access to undefined variables. ES modules are widely supported in modern browsers and Node.js.