I'm very new to JavaScript (I come from a Java background) and I am trying to do some financial calculations with small amounts of money.
My original go at this was:
<script type="text/javascript"> var normBase = ("[price]").replace("$", ""); var salesBase = ("[saleprice]").replace("$", ""); var base; if (salesBase != 0) { base = salesBase; } else { base = normBase; } var per5 = (base - (base * 0.05)); var per7 = (base - (base * 0.07)); var per10 = (base - (base * 0.10)); var per15 = (base - (base * 0.15)); document.write ( '5% Off: $' + (Math.ceil(per5 * 100) / 100).toFixed(2) + '<br/>' + '7% Off: $' + (Math.ceil(per7 * 100) / 100).toFixed(2) + '<br/>' + '10% Off: $' + (Math.ceil(per10 * 100) / 100).toFixed(2) + '<br/>' + '15% Off: $' + (Math.ceil(per15 * 100) / 100).toFixed(2) + '<br/>' ); </script> This worked well except it always rounded up (Math.ceil). Math.floor has the same issue, and Math.round is also no good for floats.
In Java, I would have avoided the use of floats completely from the get-go, however in JavaScript there does not seem to be a default inclusion of something comparable (OMG WHY!?!?!?!).
So, my SO-fu has led me to this post: https://stackoverflow.com/questions/744099/is-there-a-good-javascript-bigdecimal-library
The problem is, all the libraries mentioned are either broken or for a different purpose. The jsfromhell.com/classes/bignumber library is very close to what I need, however I'm having bizarre issues with its rounding and precision... No matter what I set the Round Type to, it seems to decide on its own. So for example, 3.7107 with precision of 2 and round type of ROUND_HALF_UP somehow winds up as 3.72 when it should be 3.71.
I also tried @JasonSmith BigDecimal library (a machined port from Java's BigDecimal), but it seems to be for node.js which I don't have the option of running.
How can I accomplish this using vanilla JavaScript (and be reliable) or is there a modern (ones mentioned above are all years old now) library that I can use that is maintained and is not broken?