$Dhruv👨‍💻

Building what I don’t fully understand yet systems self everything

[$Dhruv👨‍💻 @dcodejs]

In Node.js both process.nextTick() and queueMicrotask() run between event loop phases but nextTick runs first Overusing nextTick can block the event loop and starve I/O queueMicrotask is safer but still not free Use them wisely tiny tools huge impact

[$Dhruv👨‍💻 @dcodejs]

@faircitoo Yeah real time stuff humbles you fast

[$Dhruv👨‍💻 @dcodejs]

When a WebSocket client sends data it adds 4 extra bytes a masking key The server uses that key to decode the message

But when the server replies it doesn’t add those 4 bytes it just sends the data as-is

[$Dhruv👨‍💻 @dcodejs]

Kafka design is brilliant It acts like queue + pub/sub at the same time

In a partition only one consumer in a group gets the data queue style

With multiple consumer groups each group gets the data pub/sub style

One system two powerful patterns

[$Dhruv👨‍💻 @dcodejs]

SSDs don’t really edit data in place Once data is written to a NAND page it can’t just be changed To update it the SSD writes the new data elsewhere marks the old page as invalid and later erases a whole block at once All this juggling is why SSDs feel so fast and reliable

[$Dhruv👨‍💻 @dcodejs]

When a WebSocket starts the client sends a key The server adds a magic string hashes it encodes it and sends it back If it matches the handshake is complete and the connection upgrades

[$Dhruv👨‍💻 @dcodejs]

WebSocket is the most underrated protocol Everybody thinks they know WebSocket but most don’t know anything beyond ‘real-time’ I was the same until I dug deeper It’s way more powerful and tricky than it looks

[$Dhruv👨‍💻 @dcodejs]

DMA lets peripherals access memory directly bypassing CPU VM switches reducing latency for high throughput lO Keyboards mice gain little CPU suffices DMA compromise = full memory access risk Too many processes hurt cache & scheduling Secure IOMMU configs help mitigate DMA threats

[$Dhruv👨‍💻 @dcodejs]

@PAWARsoham_ Node.js handles it by default but you can tweak the highWaterMark if you need finer control

[$Dhruv👨‍💻 @dcodejs]

In Node js every request is a stream It buffers about 16KB by default When full Node pauses writes After draining flow resumes This pause resume keeps memory safe like the stream knows when to breathe

[$Dhruv👨‍💻 @dcodejs]

When you connect() to a TCP server your app doesn’t do the 3 way handshake The kernel handles it Only after it’s complete does the kernel tell your app

Hey I’ve got a connection for you

[$Dhruv👨‍💻 @dcodejs]

Node.js is great but sometimes you need raw speed That’s where C++ addons come in

You can write performance heavy logic in C++ compile it with node-gyp and then just require() it like any other module

Boom your Node app runs native binary code under the hood

[$Dhruv👨‍💻 @dcodejs]

Node.js is single threaded by default… but you’ve got two ways to scale 👇

Worker Threads run in same process share memory good for CPU work but limited cores

Child Processes spin up separate Node.js instances with cluster

Cluster can balance with round robin or let OS decide

[$Dhruv👨‍💻 @dcodejs]

@Abhinavstwt Maybe we only notice the 21 year olds because they remind us of when we first started dreaming big

[$Dhruv👨‍💻 @dcodejs]

In Node js server.listen(3000) often starts faster than server.listen(3000, "localhost")
Why?
Without a hostname it binds straight to 0.0.0.0 all interfaces
With "localhost" Node has to resolve the name first usually through DNS or the hosts file

[$Dhruv👨‍💻 @dcodejs]

In Nodejs server.listen(3000) often starts up faster than server.listen(3000, "localhost")

Why?

Without the hostname it just binds straight to 0.0.0.0 (all interfaces)

With "localhost" Node has to resolve the name first usually via DNS/hosts file which adds a little overhead

[$Dhruv👨‍💻 @dcodejs]

When multiple clients connect to a socket errors get queued in the pending callbacks list

If one connection fails while another succeeds Node.js will process success first

But… if the IP is loopback (127.0.0.1) it jumps to high priority in the queue!

[$Dhruv👨‍💻 @dcodejs]

@PixPerk_ For sure In the end its all trade offs speed cost reliability The ‘right’ answer isn’t universal its whatever lines up with what your system actually needs

[$Dhruv👨‍💻 @dcodejs]

@Abhishekcur Rust borrow checker feels harsh at first but over time you see its not punishment its protection That hug is the safety of knowing your code won’t betray you