What problem are you facing?

Large doubles that stringify with an exponential component will be suffixed with a trailing ".0". This will successfully roundtrip in JavaScript, because parseFloat begins ignoring a string once it encounters an invalid character. Other languages like Java will throw an exception for the incorrect formatting.

const d = new BSON.Double(Number.MAX_VALUE);
d.toExtendedJSON()
// { '$numberDouble': '1.7976931348623157e+308.0' }

What driver and relevant dependency versions are you using?

Introduced in BSON v4.7.1

Steps to reproduce?

Launch jshell

jshell> Double.valueOf("1.7976931348623157e+308.0")
|  Exception java.lang.NumberFormatException: For input string: "1.7976931348623157e+308.0"
|        at FloatingDecimal.readJavaFormatString (FloatingDecimal.java:2054)
|        at FloatingDecimal.parseDouble (FloatingDecimal.java:110)