Can google app script use external library in google app script that can do float number calculation, like bigdecimal?
when I do
var i =  1.15 - 1.12 
console.log(i); 
then i = 0.029999999999999805
Can google app script use external library in google app script that can do float number calculation, like bigdecimal?
when I do
var i =  1.15 - 1.12 
console.log(i); 
then i = 0.029999999999999805
Just to answer the question if it's possible, the answer is Yes, based on this SO post.
However if you wanted to round it up to 2 decimal places only (or more), you don't have to resort to external library, use Math.round:
function floatNumber(){
    var myInt =  1.15 - 1.12 ;
       myInt = Math.round(myInt * 100) / 100;
       Logger.log(myInt);
       //output 0.03
       //if you want 3 decimal places use /1000, and so on.
}