Round a number to 2 decimal places in JavaScript

function roundTo2(num) {
  return Math.round( ( num + Number.EPSILON ) * 100 ) / 100;
}

Rounding a number in JavaScript can be tricky in some situations when using floating-point numbers. The problem is that floating-point numbers cannot represent all decimals precisely in binary. This can lead to unexpected results, such as 0.1 + 0.2 === 0.3 returning false  

To eliminate this problem use the Number.EPSILON property, that represents the difference between 1 and the smallest floating-point number greater than 1. 

Some tutorials propose to use the toFixed method, that formats the number and also rounds it if needed, but it also suffers from the edge cases.