MongoDB types in Node.js

Question

Is there a node.js module that allows my application to have the same types as MongoDB:

http://docs.mongodb.org/manual/reference/bson-types/

For example, in my node.js app, I want it to have full understanding of the Integer type, but node.js doesn't recognize anything but Number out of the box to my understanding.

Answer 1

node.js doesn't recognize anything but Number out of the box to my understanding.

Well, that's a design decision of JavaScript. JavaScript only has a Number type, which is, if the implementation follows the standard's recommendation, represented as IEEE-754 double precision floating point number. That hides much of the complexity of short vs. long vs. float vs. double and all the other numeric types that are common in most other languages. It's also a good compromise, because they have integer precision up to 2^53 - 1, so you rarely need something outside this range, most of the time, and if you do, a long usually doesn't cut it either...

MongoDB, on the other hand, is written in C++ and is thus much closer to the gritty details of how data is actually stored in memory. Bridging that gap isn't trivial.

Is there a node.js module that allows my application to have the same types as MongoDB?

In a way, you're battling your underlying programming language. If such a module existed, it would also have to somehow implement a whole lot of operations, e.g. long addition (for results > 2^53-1) in a fundamentally different way. For instance, it could do this by converting the digits to a string and adding the individual digits manually, which would be atrociously slow.

Something like this happens in the mongo shell, e.g. for very long integers it uses a syntax like NumberLong("1223"). But it doesn't re-implement the operations, it falls back to regular V8 JavaScript. Proof:

> var foo = NumberLong("36028797018963968") // 2^55
> var foo2 = foo + NumberLong("1")
> foo2
36028797018963970 // should be 36028797018963969

Alternatively, such a module could be a native module that used the existing implementations of a native programming language such as C++. There's a node module called 'edge' that apparently does it for C#. However, that comes with quite a bit of complexity because crossing language borders requires marshalling, which is both expensive and tricky to get right.

In other words: getting a truly different set of types requires another programming language. Making your code roughly stick to your schema is possible, e.g. via mongoose or via coding discipline, but it won't make JS strongly typed.