I'm curious what you're comparing JavaScript to. Decimal is the native numeric datatype for the stored procedure language of the database I use. Otherwise, even in languages that have a decimal class in their standard library, it's usually pretty clunky to use; no better than, say, https://github.com/MikeMcl/decimal.js/ C# is perhaps the best among mainstream languages, although its implementation is a bit weird.

What is clunky about decimal type? You declare a decimal variable and then use it exactly like any other numeric type. Here is an example: https://dotnetfiddle.net/jjJHA6