#73 Explain setImmediate() in JavaScript. How it is different from process.nextTick()

🔹 setImmediate() in JavaScript

setImmediate() is a Node.js-specific function that schedules a callback to run after the current poll phase of the event loop, but before any I/O or timers.

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✅ Syntax:

setImmediate(() => {
  console.log("This runs in the check phase of the event loop");
});

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🔹 process.nextTick()

process.nextTick() schedules a callback to be invoked immediately after the current operation completes, before any other I/O events, timers, or setImmediate().

process.nextTick(() => {
  console.log("Runs before setImmediate and setTimeout");
});

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⚔️ Key Differences between setImmediate() and process.nextTick():

• Execution Timing:
  • process.nextTick() runs before the event loop continues (within the same phase).
  • setImmediate() runs on the check phase, after I/O events are processed.
• Use Case:
  • Use process.nextTick() for short, immediate tasks (microtasks).
  • Use setImmediate() for deferring execution until the end of the event loop cycle (macrotasks).
• Risk:
  • Too many nextTick() calls can starve the event loop (since they run before anything else).

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🔧 Example:

console.log("Start");

process.nextTick(() => {
  console.log("Next tick");
});

setImmediate(() => {
  console.log("Set Immediate");
});

console.log("End");

📤 Output:

Start
End
Next tick
Set Immediate