[BUG]: edge case for dfs

[shrivalidutt]

Description

If you start DFS with a node that doesn't exist in the graph, it will lead to an error when trying to access this.connections[currNode].

Expected Behavior

When the method is called with a valid node that exists in the graph, it should perform a depth-first search (DFS) starting from that node. It will explore all connected nodes and return true if it finds a node that matches the targetValue.

Actual Behavior

If the method was called with a node that doesn't exist in the graph:

It would attempt to access this.connections[currNode] in the while loop, leading to an error.
This would crash the method and potentially halt the program, resulting in a poor user experience.

Steps to reproduce (if applicable)

No response

Additional information

No response

[appgurueu]

Not a bug. If the precondition is violated, the function is allowed to crash, and this is to be expected. We could add some more error handling to throw a more useful error in this case, but I don't consider this necessary, and it would further clutter the implementation.