..:: 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 1303916 83272 ?       Ssl  Oct24 430:51 node /home/sasa/.pm2/modules/pm2-logrotate/node_modules/pm2-logr
sasa        1200  1.0  0.8 11724544 140980 ?     Ssl  Oct24 773:36 node /home/sasa/dex8/dex8-api/starter.js
sasa        1208  0.4  0.4 1305000 73884 ?       Ssl  Oct24 310:31 node /home/sasa/dex8/dex8-panel/server/index.js
sasa        1224  1.0  0.7 11852100 117888 ?     Ssl  Oct24 741:51 node /home/sasa/dex8/dex8-www/server/index.js
sasa        1236  0.6  0.6 11813900 99756 ?      Ssl  Oct24 488:14 node /home/sasa/mikosoft_hr/www-mikosoft-hr/server/index.js
sasa        1255  0.9  0.5 1330860 84676 ?       Ssl  Oct24 657:49 node /home/sasa/mikosoft-info/api-mikosoft-info/starter.js
sasa        1257  0.4  0.4 1301672 70640 ?       Ssl  Oct24 315:46 node /home/sasa/mikosoft-info/www-mikosoft-info/server/index.js
sasa        1289  0.4  0.4 1297580 66268 ?       Ssl  Oct24 310:29 node /home/sasa/dex8/dex8-kiosk/server/index.js
sasa        1363  3.5  2.9 12175228 483796 ?     Ssl  Oct24 2571:02 node /home/sasa/voovuu/voovuu-pub/server/index.js
sasa        1449  0.4  0.3 1232104 64272 ?       Ssl  Oct24 326:20 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1528  2.0  2.7 33120988 450596 ?     Ssl  Oct24 1454:51 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1529  0.4  0.3 1100900 64740 ?       Ssl  Oct24 325:27 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1606  0.4  0.3 1100644 64968 ?       Ssl  Oct24 326:39 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1607  0.4  0.3 1101156 64812 ?       Ssl  Oct24 325:35 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1705  0.4  0.4 1102184 66580 ?       Ssl  Oct24 325:19 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1706  0.4  0.3 1101412 64880 ?       Ssl  Oct24 324:46 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1805  0.4  0.4 1167968 66440 ?       Ssl  Oct24 325:44 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1807  0.4  0.3 1100640 64588 ?       Ssl  Oct24 318:10 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1885  0.4  0.4 1102952 66692 ?       Ssl  Oct24 319:43 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1886  2.3  1.0 11879176 176544 ?     Ssl  Oct24 1716:25 node /home/sasa/mikosoft-info/crypto-mikosoft-info/server/index.
sasa     2628167  1.0  0.7 1174188 130580 ?      Ssl  Nov04 569:00 node /home/sasa/voovuu/voovuu-api/starter.js
www-data 3123328  0.0  0.0   2608   596 ?        S    17:14   0:00 sh -c ps -aux | grep node
www-data 3123330  0.0  0.0   3304   656 ?        S    17:14   0:00 grep node
sasa     3168557  0.7  0.5 11802360 92592 ?      Ssl  Nov06 422:43 node /home/sasa/mikosoft-info/dodo-mikosoft-info/server/index.js
sasa     3169051  0.5  0.5 11798664 83912 ?      Ssl  Nov06 284:10 node /home/sasa/@mikosoft/dodo-examples/server/index.js