I am making a service price tracker bot which will show something like this on price decrease:
Service price decreased from 0.10 to 0.05
If you buy right now, you could save <x>
<x> is the substracted amount or safe amount (oldPrice - newPrice).
Code for subtraction:
oldPrice - newPrice
0.10 - 0.05
// -> 0.05
While this works completely fine, but in some cases, if the service price (new or old) is like in more than 3 decimals e.g. 0.2184
The code will return weird full long number.
Examples:
0.2184 - 0.1404
// -> 0.07800000000000001
0.09 - 0.085
// -> 0.0049999999999999906
2.159 - 2.0088
// -> 0.1501999999999999
/* Rare cases */
0.1764 - 0.1134
// -> 0.063
5.675 - 2.275
// -> 3.4
5.175 - 1.775
// -> 3.4
I obviously tried things like Math.abs() and use String.replace() to remove 00 and 99, but nothing really works.
e.g.
2.159 - 2.0088
// -> 0.1501999999999999
String(2.159 - 2.0088).replace(/[09][09]+/g, "");
// -> "0.1501"
0.2184 - 0.1404
// -> 0.07800000000000001
String(0.2184 - 0.1404).replace(/[09][09]+/g, "");
// -> "0.0781"
// -> Right: "0.780"
// -> Mistakes: 0.0 and 781 instead of 780
Note: I don't really care if the result is in string.
As you already saw above, it calculates wrong or essentially removes the main 9s or 0s.
Is there any other approach or it's the best one?
