..:: Source code - 01callback.js ::..

/**
 * basic usage of callbacks
 */

/* MAIN FUNCTION */
function addnum(x, cb) {
  console.log('x=' + x);
  cb(x);
}


/* CALLBACKS */

//callback which adds 5
function cb5(a) {
  var rez = a + 5;
  console.log('a+5=' + rez);
}

//callback which adds 100
function cb100(a) {
  var rez = a + 100;
  console.log('a+100=' + rez);
}

//execute main function with callback cb5
addnum(2, cb5);

console.log();

//execute main function with callback cb100
addnum(2, cb100);


/* $node 01callback
x=2
a+5=7

x=2
a+100=102
 */

..:: NodeJS Console - 01callback.js ::..

x=2
a+5=7

x=2
a+100=102

$ps -aux | grep node (list all node processes)
sasa        1197  1.4  0.5 1326380 97936 ?       Ssl  Oct18 298:04 node /home/sasa/.pm2/modules/pm2-logrotate/node_modules/pm2-logr
sasa        1211  9.5  0.6 11708932 113672 ?     Ssl  Oct18 1910:22 node /home/sasa/dex8/dex8-api/starter.js
sasa        1218  0.4  0.5 11801072 84320 ?      Ssl  Oct18  88:01 node /home/sasa/dex8/dex8-panel/server/index.js
sasa        1219  0.7  0.6 11816976 100288 ?     Ssl  Oct18 153:07 node /home/sasa/dex8/dex8-www/server/index.js
sasa        1232  0.4  0.5 11810236 89384 ?      Ssl  Oct18  89:53 node /home/sasa/mikosoft_hr/www-mikosoft-hr/server/index.js
sasa        1248  0.6  0.5 1332664 83776 ?       Ssl  Oct18 127:47 node /home/sasa/mikosoft-info/api-mikosoft-info/starter.js
sasa        1274  0.3  0.4 1300692 67124 ?       Ssl  Oct18  62:18 node /home/sasa/mikosoft-info/www-mikosoft-info/server/index.js
sasa        1277  0.3  0.3 1298372 65028 ?       Ssl  Oct18  61:11 node /home/sasa/dex8/dex8-kiosk/server/index.js
sasa        1335  0.4  0.7 11846880 122460 ?     Ssl  Oct18  89:16 node /home/sasa/mikosoft-info/dodo-mikosoft-info/server/index.js
sasa        1337  0.6  0.7 1163264 115516 ?      Ssl  Oct18 137:04 node /home/sasa/voovuu/voovuu-api/starter.js
sasa        1385  3.7  3.8 12342312 629608 ?     Ssl  Oct18 753:59 node /home/sasa/voovuu/voovuu-pub/server/index.js
sasa        1387  0.3  0.4 11797452 81076 ?      Ssl  Oct18  66:40 node /home/sasa/@mikosoft/dodo-examples/server/index.js
sasa        1457  0.3  0.3 1099104 61256 ?       Ssl  Oct18  62:30 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1458  0.3  0.4 22280876 80256 ?      Ssl  Oct18  63:18 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1514  0.3  0.3 1099492 62572 ?       Ssl  Oct18  62:14 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1515  0.3  0.3 1099364 62748 ?       Ssl  Oct18  62:08 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1593  0.3  0.3 1099360 63372 ?       Ssl  Oct18  62:27 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1595  0.3  0.3 1099104 62588 ?       Ssl  Oct18  62:17 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1660  0.3  0.3 1099248 63020 ?       Ssl  Oct18  62:06 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1661  0.3  0.4 1102688 66720 ?       Ssl  Oct18  62:11 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1732  0.3  0.4 1102688 66464 ?       Ssl  Oct18  62:12 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1734  0.3  0.3 1099360 63096 ?       Ssl  Oct18  62:01 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1792  0.4  0.5 11803428 90468 ?      Ssl  Oct18  91:58 node /home/sasa/mikosoft-info/crypto-mikosoft-info/server/index.
sasa      367378  0.6  0.5 1332588 83204 ?       Ssl  Oct21  96:23 node /home/sasa/miko/miko-hr/api/starter.js
sasa      367471  1.2  1.0 11896336 166500 ?     Ssl  Oct21 187:00 node /home/sasa/miko/miko-hr/server/index.js
www-data 1532162  0.0  0.0   2608   528 ?        S    09:11   0:00 sh -c ps -aux | grep node
www-data 1532164  0.0  0.0   3304   644 ?        S    09:11   0:00 grep node