Understanding the Node.js Event Loop: Architecture, Differences with Browser, and Examples

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Timers: Executes callbacks scheduled by setTimeout() and setInterval().

Pending Callbacks: Handles I/O callbacks deferred to the next loop iteration.

Poll: Retrieves new I/O events; executing I/O callbacks.

Check: Executes setImmediate callbacks.

The event loop repeatedly executes these phases ensuring non-blocking I/O and high efficiency in handling numerous tasks.

Similarities:

Both use an event loop to manage asynchronous operations.

They handle similar types of tasks: timers, I/O, and high-level constructs (like Promises).

Differences:

[[See Video to Reveal this Text or Code Snippet]]

Output Explanation:

Start of script

End of script

File read callback (executed when the file reading is complete)

Immediate callback (processed in the Check phase after Poll)

Timeout callback (executed after the Poll phase in the Timers phase)

Conclusion