..:: 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         831  0.4  0.4 1300928 72484 ?       Ssl  Jun15   7:34 node /home/sasa/.pm2/modules/pm2-logrotate/node_modules/pm2-logr
sasa         843  0.4  0.6 11696264 100456 ?     Ssl  Jun15   6:56 node /home/sasa/dex8/dex8-api/starter.js
sasa         858  0.3  0.3 1032208 60920 ?       Ssl  Jun15   5:31 node /home/sasa/regoch/regoch-www/server
sasa         867  0.3  0.3 1292724 58648 ?       Ssl  Jun15   5:24 node /home/sasa/dex8/dex8-panel/server/index.js
sasa         886  0.7  0.5 11796212 83436 ?      Ssl  Jun15  12:12 node /home/sasa/dex8/dex8-www/server/index.js
sasa         888  0.3  0.4 11789848 74768 ?      Ssl  Jun15   5:49 node /home/sasa/mikosoft_hr/www-mikosoft-hr/server/index.js
sasa         904  0.6  0.4 1329612 81328 ?       Ssl  Jun15   9:52 node /home/sasa/mikosoft-info/api-mikosoft-info/starter.js
sasa         910  0.3  0.3 1295860 63900 ?       Ssl  Jun15   5:25 node /home/sasa/mikosoft-info/www-mikosoft-info/server/index.js
sasa         969  0.3  0.3 1028148 55200 ?       Ssl  Jun15   5:19 node /home/sasa/dex8/dex8-kiosk/server/index.js
sasa         970  0.4  0.5 11814192 94720 ?      Ssl  Jun15   7:28 node /home/sasa/mikosoft-info/dodo-mikosoft-info/server/index.js
sasa        1010  0.4  0.5 1138968 92204 ?       Ssl  Jun15   6:55 node /home/sasa/voovuu/voovuu-api/starter.js
sasa        1016  0.6  0.6 11809128 105032 ?     Ssl  Jun15   9:41 node /home/sasa/voovuu/voovuu-pub/server/index.js
sasa        1086  0.3  0.4 11595744 74524 ?      Ssl  Jun15   5:43 node /home/sasa/@mikosoft/dodo-examples/server/index.js
sasa        1089  0.3  0.3 1099356 64744 ?       Ssl  Jun15   5:35 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1159  0.3  0.3 1099360 64404 ?       Ssl  Jun15   5:34 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1160  0.3  0.3 1099356 64536 ?       Ssl  Jun15   5:33 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1241  0.3  0.3 1100696 63280 ?       Ssl  Jun15   5:31 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1242  0.3  0.4 22277820 76236 ?      Ssl  Jun15   5:48 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1323  0.3  0.3 1099356 63556 ?       Ssl  Jun15   5:32 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1324  0.3  0.3 1099360 64236 ?       Ssl  Jun15   5:32 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1398  0.3  0.3 1099360 64680 ?       Ssl  Jun15   5:32 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1400  0.3  0.3 1099356 64472 ?       Ssl  Jun15   5:33 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1465  0.3  0.3 1099360 64516 ?       Ssl  Jun15   5:30 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1475  0.3  0.6 11809828 105064 ?     Ssl  Jun15   6:09 node /home/sasa/mikosoft-info/crypto-mikosoft-info/server/index.
www-data   77385  0.0  0.0   2608   596 ?        S    05:08   0:00 sh -c ps -aux | grep node
www-data   77387  0.0  0.0   3304   724 ?        S    05:08   0:00 grep node