Node.js: What is the difference between process.nextTick() and setImmediate() in Node.js?

nextTick() — executes before event loop. setImmediate() — executes in check phase.

process.nextTick():

• Executes immediately after current operation.
• Before event loop continues.
• Can starve event loop.
• Higher priority.

1process.nextTick(() => {
2    console.log("nextTick");
3});

setImmediate():

• Executes in check phase.
• After event loop.
• Lower priority.
• Part of event loop.

1setImmediate(() => {
2    console.log("immediate");
3});

Execution order:

1// In I/O callback:
2setImmediate(() => console.log("immediate"));
3process.nextTick(() => console.log("nextTick"));
4// Output: nextTick, immediate

Key difference:

• nextTick — before event loop.
• setImmediate — in event loop.