How is setTimeout implemented in node.js

Question

I was wondering if anybody knows how setTimeout is implemented in node.js. I believe I have read somewhere that this is not part of V8. I quickly tried to find the implement

Answer 1

No problem with many timers! When uv loop call poll, it pass timeout argument to it with closest timer of all timers.

[closest timer of all timers]
https://github.com/joyent/node/blob/master/deps/uv/src/unix/timer.c #120

RB_MIN(uv__timers, &loop->timer_handles)  

[pass timeout argument to poll api]
https://github.com/joyent/node/blob/master/deps/uv/src/unix/core.c #276

timeout = 0;  
if ((mode & UV_RUN_NOWAIT) == 0)  
    timeout = uv_backend_timeout(loop);  

uv__io_poll(loop, timeout); 

Note: on Windows OS, it's almost same logic