javascript - Exporting multiple functions with arguments - Stack Overflow

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All I am trying to do is to export two functions from a module. One function taking an argument and the other with no argument:

function initClass(params)
{
   return new Promise( (resolve, reject) => {
        if (!wallet) {
            wallet = new WalletClient(params);
            resolve(wallet);
        } else {
            console.log('Wallet is initialized');
            resolve(wallet);
        }
});
}

function getInstance()
{
   return wallet;
}

For initClass(params) only, I can do this as:

module.exports = (params) => {
   initClass(params)
}

And then I call this as:

var init = require('./class.js')(params).initClass(params);

This works fine.

Now, for me to export getInstance() as well, I have tried to do the following but it doesn't seem to work.

module.exports = (params) => {
   initClass(params),
   getInstance
}

This plaints that there is no function getInstance.

Then I tried this:

module.exports.init = (params) => {
   initClass(params)
}

module.exports.instance = {
   getInstance
}

Then call them as:

var init = require('./class.js').init(params).initClass(params);

What is the proper way to export multiple functions like this? Thank you.

All I am trying to do is to export two functions from a module. One function taking an argument and the other with no argument:

function initClass(params)
{
   return new Promise( (resolve, reject) => {
        if (!wallet) {
            wallet = new WalletClient(params);
            resolve(wallet);
        } else {
            console.log('Wallet is initialized');
            resolve(wallet);
        }
});
}

function getInstance()
{
   return wallet;
}

For initClass(params) only, I can do this as:

module.exports = (params) => {
   initClass(params)
}

And then I call this as:

var init = require('./class.js')(params).initClass(params);

This works fine.

Now, for me to export getInstance() as well, I have tried to do the following but it doesn't seem to work.

module.exports = (params) => {
   initClass(params),
   getInstance
}

This plaints that there is no function getInstance.

Then I tried this:

module.exports.init = (params) => {
   initClass(params)
}

module.exports.instance = {
   getInstance
}

Then call them as:

var init = require('./class.js').init(params).initClass(params);

What is the proper way to export multiple functions like this? Thank you.

• javascript
• node.js
• node-modules

Share Improve this question Follow edited Jul 19, 2019 at 8:48 madu asked Jul 19, 2019 at 8:21 madumadu 5,4701414 gold badges6565 silver badges104104 bronze badges 5

• 1 Regardless of import/export, to call initClass chained to init, init would have to return something that has initClass on its prototype - which it clearly doesn't – baao Commented Jul 19, 2019 at 8:25
• 1 Your var init = require('./class.js')(params).initClass(params); call does not look valid. Or are you returning something from the exported function? – Bergi Commented Jul 19, 2019 at 8:32
• @Bergi Yes, I am exporting an instantiated class from initClass – madu Commented Jul 19, 2019 at 8:36
• 1 @madu Then please show the actual code. – Bergi Commented Jul 19, 2019 at 8:44
• @Bergi added the code of initClass. Thank you. – madu Commented Jul 19, 2019 at 8:48

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3 Answers 3

Sorted by: Reset to default 3

You're making it more plex than needed. Once you have your functions defined, you can export it with this:

module.exports = {
  initClass,
  getInstance
}

To use it, you do this:

const init = require("./class.js");
init.initClass(params);
const instance = init.getInstance();

What you're exporting from the module is an object (which I've named init in the example above) that contains two functions. You don't have to pass arguments to the functions at the time you require.

module.exports is basically an object with keys which can refer to any variables/functions of your file.In your case,

module.exports.initClass = function (params){
...
}

module.exports.getInstance = function (){
}

When importing it

var init = require('./class.') // init object has two keys -> initClass and getInstance
 init.initClass('abc')
 init.getInstance()

If i'm understanding correctly you are trying to export multiple methods if that is the case simple use this.

   module.exports = {
        method: function() {},
        otherMethod: function(parmas) {}
    }

In your code use like this.

 var init = require('./class.js');
    init.method()
    init.otherMethond(paramObj)

If you want below scenario you need to check out about method chaining.

var init = require('./class.js').init(params).initClass(params);

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