Correct async function export in node.js

Question

I had my custom module with following code:

module.exports.PrintNearestStore = async function PrintNearestStore(session, lat, lon) {
...
}

It worked fine if call the function outside my module, however if I called inside I got error while running:

(node:24372) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): ReferenceError: PrintNearestStore is not defined

When I changed syntax to:

module.exports.PrintNearestStore = PrintNearestStore;

var PrintNearestStore = async function(session, lat, lon) {

}

It started to work fine inside module, but fails outside the module - I got error:

(node:32422) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): TypeError: mymodule.PrintNearestStore is not a function

So I've changed code to:

module.exports.PrintNearestStore = async function(session, lat, lon) {
    await PrintNearestStore(session, lat, lon);
}

var PrintNearestStore = async function(session, lat, lon) {
...
}

And now it works in all cases: inside and outside. However want to understand semantics and if there is more beautiful and shorter way to write it? How to correctly define and use async function both: inside and outside (exports) module?

Answer 1

Error with first case: PrintNearestStore - Function expression, so this name not available outside.

error with second case: using variable, instead Function declaration. In this case, declaration of variable PrintNearestStore are hoisted, so, you can use this name before line var PrintNearestStore = ..., but in this case value would be undefined.

So, simplest solution change second variant like this:

module.exports.PrintNearestStore = PrintNearestStore;

async function PrintNearestStore(session, lat, lon) {

}

Answer 2

an alternative would be to export like this. // foo.js

export async function foo(){ 
 console.log('I am greatest of all.'); // for the person who reads it, just say it.
}

then use it in other scripts like

import { foo } from './foo'

foo();

Answer 3

export let handlePostStore = async (data) => {
    console.log('post');
    return data;
};

// to import 
import { handlePostStore } from 'your_path_here';

// to call it 
handlePostStore(data)

Answer 4

Some examples:

module.exports.func1 = async function func1(id) {  // name is preferred by linter
  //
};

module.exports.func1 = async function (id) { // ok
  //
};

module.exports.func1 = async (id) => { // simpler
  //
};