How does node process concurrent requests?

Question

I have been reading nodejs lately, trying to understand how it handles multiple concurrent requests, I know nodejs is a single threaded event loop based architecture, at a g

Answer 1

The V8 JS interpeter (ie: Node) is basically single threaded. But, the processes it kicks off can be async, example: 'fs.readFile'.

As the express server runs, it will open new processes as it needs to complete the requests. So the 'readImage' function will be kicked off (usually asynchronously) meaning that they will return in any order. However the server will manage which response goes to which request automatically.

So you will NOT have to manage which readImage response goes to which request.

So basically, T1 and T2, will not return concurrently, this is virtually impossible. They are both heavily reliant on the Filesystem to complete the 'read' and they may finish in ANY ORDER (this cannot be predicted). Note that processes are handled by the OS layer and are by nature multithreaded (in a modern computer).

If you are looking for a queue system, it should not be too hard to implement/ensure that images are read/returned in the exact order that they are requested.