..:: 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         914  0.5  0.5 1306896 84892 ?       Ssl  Aug04 344:10 node /home/sasa/.pm2/modules/pm2-logrotate/node_modules/pm2-logr
sasa         935  0.7  0.8 11786584 132940 ?     Ssl  Aug04 508:47 node /home/sasa/dex8/dex8-api/starter.js
sasa         938  0.4  0.4 1307036 76556 ?       Ssl  Aug04 292:37 node /home/sasa/regoch/regoch-www/server
sasa         945  0.3  0.4 1303752 71420 ?       Ssl  Aug04 248:54 node /home/sasa/dex8/dex8-panel/server/index.js
sasa         947  0.7  0.6 11829428 109316 ?     Ssl  Aug04 506:44 node /home/sasa/dex8/dex8-www/server/index.js
sasa         966  0.5  0.6 11808976 98528 ?      Ssl  Aug04 383:56 node /home/sasa/mikosoft_hr/www-mikosoft-hr/server/index.js
sasa         980  0.8  0.5 1330216 83712 ?       Ssl  Aug04 527:44 node /home/sasa/mikosoft-info/api-mikosoft-info/starter.js
sasa         997  0.3  0.4 1303104 71824 ?       Ssl  Aug04 251:39 node /home/sasa/mikosoft-info/www-mikosoft-info/server/index.js
sasa        1021  0.3  0.4 1297448 65588 ?       Ssl  Aug04 247:57 node /home/sasa/dex8/dex8-kiosk/server/index.js
sasa        1065  0.6  0.6 11834076 111680 ?     Ssl  Aug04 422:51 node /home/sasa/mikosoft-info/dodo-mikosoft-info/server/index.js
sasa        1074  0.6  0.6 1148752 103720 ?      Ssl  Aug04 412:36 node /home/sasa/voovuu/voovuu-api/starter.js
sasa        1136  0.7  0.9 11850660 152108 ?     Ssl  Aug04 478:45 node /home/sasa/voovuu/voovuu-pub/server/index.js
sasa        1148  0.4  0.4 11794644 78364 ?      Ssl  Aug04 274:53 node /home/sasa/@mikosoft/dodo-examples/server/index.js
sasa        1197  0.3  0.3 1100140 63040 ?       Ssl  Aug04 256:29 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1199  0.4  0.4 22277756 77568 ?      Ssl  Aug04 260:35 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1308  0.3  0.4 1102688 66748 ?       Ssl  Aug04 255:41 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1325  0.3  0.4 1102688 66256 ?       Ssl  Aug04 255:28 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1393  0.8  0.8 22325752 146096 ?     Ssl  Aug04 523:35 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1395  0.3  0.4 1102956 66932 ?       Ssl  Aug04 256:40 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1489  0.3  0.4 1102432 66092 ?       Ssl  Aug04 256:34 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1496  0.3  0.3 1100640 65304 ?       Ssl  Aug04 255:19 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1607  0.3  0.4 1102688 66172 ?       Ssl  Aug04 255:54 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1608  0.3  0.4 1102944 66468 ?       Ssl  Aug04 254:42 node /home/sasa/dex8/dex8-worker/starter.js
sasa        1686  1.4  5.0 12560252 827076 ?     Ssl  Aug04 963:56 node /home/sasa/mikosoft-info/crypto-mikosoft-info/server/index.
www-data  972945  0.0  0.0   2608   524 ?        S    14:52   0:00 sh -c ps -aux | grep node
www-data  972947  0.0  0.0   3304   648 ?        S    14:52   0:00 grep node
sasa     1371685  0.4  0.5 11805136 90888 ?      Ssl  Aug16 211:28 node /home/sasa/mikosoft-info/solar-wind-energy/server/index.js
sasa     1460918  0.4  0.3 1300136 65060 ?       Ssl  Aug17 209:38 node /home/sasa/sites-nodejs/oxygen-free-copper/server.js