如何在 NodeJS 中导出模块及其子模块？

Question

I want to create a Velbus (home automation) library to import in any project with Node.JS. However, there are plenty of function (sometime 6 or more) on each kind of Velbus modules, so I want to split my actual library into submodules (primitives_blind.js, primitives_relay.js, primitives_tempSensor.js, etc.) I can import them in my main library VelbusLib.js, but I don't know how to allow a user to only import my main module, but use function from submodules.

Example: primitives_blind.js

function blindUP(adr, part) { ... }
function blindDOWN(adr, part) { ... }
function blindStatus(adr, part) { ... }
module.exports = { blindUP, blindDOWN, blindStatus }

VelbusLib.js

const blind = require('./primitives_blind.js')

index.js (an App)

const velbusLib = require('./VelbusLib.js')
...
velbusLib.blindUP(0x40, 1) // blind.blindUP() not wanted, because user have to import all submodules

Of course, it's not possible to export function imported

module.exports = {
    CheckSum,
    Cut,
    // blindUP or blind.blindUP aren't possible

A small schema is often better than a long discuss: Can someone explain to me the "State-of-the-art" about this? Thanks:)

Answer 1

I suspect you're looking for object literal spread syntax

const blind = require('./primitives_blind.js')
module.exports = {
    CheckSum,
    Cut,
    ...blind,
};

which essentially does the same as

const blind = require('./primitives_blind.js')
module.exports = {
    CheckSum,
    Cut,
    blindUP: blind.blindUP,
    blindDOWN: blind.blindDOWN,
    blindStatus: blind.blindStatus,
};

However, since you were asking for the state of the art: use ES6 module syntax for the whole library, not CommonJS module.exports , With that it would be

export * from './primitives_blind.js';

Answer 2

After much research, it appears that's not possible to have many submodules (ModA, ModB, ModC) and import a module ModX in an app "APP" and use import ModA, ModB, ModC from it.

"APP" must import A, B, C too if you need these modules in it. "APP" can call components from ModX module and ModX module can call components from ModA, ModB, ModC

This concept maybe in relation with "tight coupling" pattern...

The next question for me is " how to avoid file of code with more than 1000 lines? "