JS namespaces (modules)

Hello,
Is it possible to define somehow module/namespace on JS level?
Let's say I have:
```
mod features {
#[node_bindgen]
pub fn feature_a() -> Result<...> { .... }
}

mod tools {
#[node_bindgen]
pub fn tool_a() -> Result<...> { .... }
}
```
On js level I would like to see it as:
```
let rustcore = require('rustcore.node');
rustcore.features.feature_a();
rustcore.tools.tool_a();
```
Sorry if question is trivial, but didn't find any kind of solution for that.

No file, test, or entry point is named; begin by locating the existing Node.js module export path and how Rust modules are exposed. Done means determining whether nested features and tools namespaces can be represented in JavaScript, and documenting or implementing the required behavior.

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