The current code does not show any irregularities but could be improved in terms of documentation and readability. Here are some suggested improvements:

1. Remove unnecessary curly braces and spaces between methods, make them more consistent.
2. Document method names properly with descriptions to improve understanding.

To optimize performance while keeping the same functionality:

• Use map instead of forEach, it's faster when dealing with arrays.
• If there needs to be an update event firing after each selection change operation (onSelectionChange), consider using hooks like useEffect.
• Consider refactoring selectors and state handling into a separate logic component to simplify implementation.

There are no identified differences between the two versions that suggest any irregularities, potential issues, or optimizations; both look to operate similarly under the current version of Node.js. It's best to proceed with caution if updates have been made outside our standard scope as these can sometimes introduce new bugs or errors not caught during testing or verification.

To ensure smooth operation please verify with more thorough checks on specific aspects such data validation, event handling, and performance tests against real-world conditions. If necessary, update dependencies and check compatibility with any newly introduced functionality or changes.

Here is an initial review:

In the provided code snippet, there appear to be no obvious problems, potential issues or recommendations for optimizing performance. It's important to note that the last two methods of "cloneRoute" and "onDelete", although not defined, seem relevant for further development and should likely not be removed unless specific use-cases dictate otherwise.

However, it's recommended to thoroughly test with various scenarios before proceeding into production to ensure stability and compatibility. If you encounter any errors during testing, debugging can then begin. Additionally, always keep in mind to maintain versioning standards when updating components like these.

This analysis considers the current knowledge cutoff date, assuming no new significant issues were discovered prior to its creation. The exact context for any optimizations would depend on future updates and needs such as handling different routes and state across clones/drops etc.