..:: 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  0.4  0.4 1302684 78828 ?       Ssl  Oct24  51:01 node /home/sasa/.pm2/modules/pm2-logrotate/node_modules/pm2-logr
sasa        1200  0.8  0.8 11719248 135984 ?     Ssl  Oct24  92:17 node /home/sasa/dex8/dex8-api/starter.js
sasa        1207  0.3  0.4 1302492 70824 ?       Ssl  Oct24  38:37 node /home/sasa/regoch/regoch-www/server
sasa        1208  0.3  0.4 1302608 69472 ?       Ssl  Oct24  36:39 node /home/sasa/dex8/dex8-panel/server/index.js
sasa        1224  0.7  0.6 11827392 105668 ?     Ssl  Oct24  86:07 node /home/sasa/dex8/dex8-www/server/index.js
sasa        1236  0.4  0.5 11810572 95036 ?      Ssl  Oct24  50:28 node /home/sasa/mikosoft_hr/www-mikosoft-hr/server/index.js
sasa        1255  0.6  0.5 1328956 81952 ?       Ssl  Oct24  69:28 node /home/sasa/mikosoft-info/api-mikosoft-info/starter.js
sasa        1257  0.3  0.4 1300548 68556 ?       Ssl  Oct24  37:17 node /home/sasa/mikosoft-info/www-mikosoft-info/server/index.js
sasa        1289  0.3  0.3 1296508 64520 ?       Ssl  Oct24  36:23 node /home/sasa/dex8/dex8-kiosk/server/index.js
sasa        1292  0.4  0.5 11820720 94616 ?      Ssl  Oct24  51:42 node /home/sasa/mikosoft-info/dodo-mikosoft-info/server/index.js
sasa        1361  0.7  0.6 1157528 113268 ?      Ssl  Oct24  81:20 node /home/sasa/voovuu/voovuu-api/starter.js
sasa        1363  2.7  2.3 12147864 389396 ?     Ssl  Oct24 298:15 node /home/sasa/voovuu/voovuu-pub/server/index.js
sasa        1441  0.3  0.4 11793416 77324 ?      Ssl  Oct24  39:31 node /home/sasa/@mikosoft/dodo-examples/server/index.js
sasa        1449  0.3  0.3 1165288 63592 ?       Ssl  Oct24  38:12 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1528  1.5  0.9 22351428 161276 ?     Ssl  Oct24 169:24 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1529  0.3  0.3 1099364 63516 ?       Ssl  Oct24  38:07 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1606  0.3  0.3 1098340 62104 ?       Ssl  Oct24  38:20 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1607  0.3  0.3 1099620 63612 ?       Ssl  Oct24  38:11 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1705  0.3  0.3 1099368 64416 ?       Ssl  Oct24  38:08 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1706  0.3  0.3 1099108 63516 ?       Ssl  Oct24  38:03 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1805  0.3  0.3 1099872 64896 ?       Ssl  Oct24  38:08 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1807  0.3  0.3 1099872 64120 ?       Ssl  Oct24  37:33 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1885  0.3  0.3 1099112 64708 ?       Ssl  Oct24  37:36 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1886  0.8  0.7 11820384 118532 ?     Ssl  Oct24  93:44 node /home/sasa/mikosoft-info/crypto-mikosoft-info/server/index.
www-data 1776168  0.0  0.0   2608   596 ?        S    04:08   0:00 sh -c ps -aux | grep node
www-data 1776170  0.0  0.0   3304   724 ?        S    04:08   0:00 grep node