..:: Source code - 020number_float_rounding_error.js ::..

/**
 * Binary floating point
 */
var x, y, z, num;

x = 0.3 - 0.2;
y = 0.2 - 0.1;
z = 0.5 - 0.4;

console.log(x); //0.09999999999999998
console.log(y); //0.1
console.log(z); //0.09999999999999998

// correction with parseFloat and toPrecision
console.log(parseFloat(z.toPrecision(12))); //0.1
 

..:: NodeJS Console - 020number_float_rounding_error.js ::..

$ node 020number_float_rounding_error.js
0.09999999999999998
0.1
0.09999999999999998
0.1
$ps -aux | grep node (list all node processes)
sasa        1194  0.5  0.5 1305092 83860 ?       Ssl  Oct24 539:06 node /home/sasa/.pm2/modules/pm2-logrotate/node_modules/pm2-logr
sasa        1208  0.4  0.4 1305000 73736 ?       Ssl  Oct24 389:19 node /home/sasa/dex8/dex8-panel/server/index.js
sasa        1224  0.9  0.8 11850472 132412 ?     Ssl  Oct24 909:20 node /home/sasa/dex8/dex8-www/server/index.js
sasa        1236  0.6  0.6 11808824 98800 ?      Ssl  Oct24 613:30 node /home/sasa/mikosoft_hr/www-mikosoft-hr/server/index.js
sasa        1255  0.8  0.5 1330860 84312 ?       Ssl  Oct24 836:25 node /home/sasa/mikosoft-info/api-mikosoft-info/starter.js
sasa        1257  0.4  0.4 1304664 73376 ?       Ssl  Oct24 396:24 node /home/sasa/mikosoft-info/www-mikosoft-info/server/index.js
sasa        1289  0.4  0.3 1290860 58928 ?       Ssl  Oct24 388:57 node /home/sasa/dex8/dex8-kiosk/server/index.js
sasa        1363  4.1  3.0 12191868 502360 ?     Ssl  Oct24 3919:54 node /home/sasa/voovuu/voovuu-pub/server/index.js
sasa        1886  2.5  1.1 11875520 180368 ?     Ssl  Oct24 2443:48 node /home/sasa/mikosoft-info/crypto-mikosoft-info/server/index.
sasa     1214480  0.3  0.4 1100680 65948 ?       Ssl  Dec28   3:20 node /home/sasa/dex8/dex8-worker/starter.js
sasa     1214483  0.3  0.4 1100800 66260 ?       Ssl  Dec28   3:19 node /home/sasa/dex8/dex8-worker/starter.js
sasa     1214536  0.3  0.4 1100804 65852 ?       Ssl  Dec28   3:20 node /home/sasa/dex8/dex8-worker/starter.js
sasa     1214544  0.3  0.4 1100776 65656 ?       Ssl  Dec28   3:22 node /home/sasa/dex8/dex8-worker/starter.js
sasa     1214588  0.3  0.3 1100804 65484 ?       Ssl  Dec28   3:19 node /home/sasa/dex8/dex8-worker/starter.js
sasa     1214617  0.3  0.4 1100672 66124 ?       Ssl  Dec28   3:18 node /home/sasa/dex8/dex8-worker/starter.js
sasa     1214641  0.3  0.3 1100392 64760 ?       Ssl  Dec28   3:15 node /home/sasa/dex8/dex8-worker/starter.js
sasa     1214671  0.3  0.3 1100384 64752 ?       Ssl  Dec28   3:16 node /home/sasa/dex8/dex8-worker/starter.js
sasa     1215731  0.4  0.6 11699744 110236 ?     Ssl  Dec28   4:21 node /home/sasa/dex8/dex8-api/starter.js
sasa     1216489  0.3  0.4 1100536 65664 ?       Ssl  Dec28   3:16 node /home/sasa/dex8/dex8-worker/starter.js
sasa     1253781  0.3  0.4 1102432 66680 ?       Ssl  03:03   1:48 node /home/sasa/dex8/dex8-worker/starter.js
www-data 1295736  0.0  0.0   2608   596 ?        S    12:05   0:00 sh -c ps -aux | grep node
www-data 1295738  0.0  0.0   3304   716 ?        S    12:05   0:00 grep node
sasa     2628167  0.9  0.7 1174632 130580 ?      Ssl  Nov04 780:03 node /home/sasa/voovuu/voovuu-api/starter.js
sasa     3168557  0.7  0.5 11821768 97428 ?      Ssl  Nov06 562:07 node /home/sasa/mikosoft-info/dodo-mikosoft-info/server/index.js
sasa     3169051  0.5  0.5 11798920 83412 ?      Ssl  Nov06 395:48 node /home/sasa/@mikosoft/dodo-examples/server/index.js