When working with file operations in Node.js using the fs module, handling asynchronous errors is crucial. Asynchronous file operations can fail due to various reasons such as file not found, permission issues, or disk full errors. Proper error handling ensures data integrity and prevents unexpected crashes in your application.

In Express.js, you can define optional route parameters by using the ? symbol after the parameter name, like /route/:param?. This makes the parameter optional, allowing it to match both routes with and without that parameter. The other options do not represent the correct way to define optional route parameters in Express.js.

To rectify this issue, you should use the npm prune --production command. This command removes unnecessary devDependencies from your node_modules directory, ensuring that only production dependencies are included in the build. Options (1) and (4) are not recommended because manually removing or upgrading devDependencies can be error-prone. Option (2) doesn't directly address the issue, and Webpack is typically used for bundling rather than dependency management.

In this scenario, you can efficiently handle multiple Promises using Promise.allSettled(). This method returns an array of results for all Promises, allowing you to handle both resolved and rejected Promises without stopping the execution of others. Promise.race() would stop execution on the first rejection, Promise.all() requires all to resolve, and Promise.any() stops on the first resolution.

Developers can specify the version of their package when publishing to the NPM registry using the npm version command followed by the desired version number, e.g., npm version 1.0.0. The other options do not perform this specific task.

The primary use case for the rest operator in function parameters is to collect multiple arguments into an array. It allows a function to accept a variable number of arguments and access them as an array. The other options are not the intended use of the rest operator in this context.

To install a specific version of a package using npm, you should use the npm install @ command. This allows you to specify the exact version you want to install. The other options do not provide the same functionality or may not work as expected.

The response.end() method is used to end the response process in an HTTP server. It finalizes the response and sends it to the client. The other options are not valid methods for ending the response.

In EJS, you can include partial views using the <%- include('partial') %> syntax. This allows you to reuse and insert content from other EJS files into your main template, helping you create modular and maintainable views. The other options are not the correct syntax for including partials in EJS.

The npm update command can be used to update the package.json file to match the actual versions installed in the node_modules directory. This command will update the version numbers of packages in package.json based on the versions currently installed.