Why is node.js module.export not returning globally?

Question

Below is my code, it is a GET request that will return a Ticket Number (I left the headers/options/auth out).

I want to know why the first console.log below returns a ticket number (as it should), but the second console log does not return a ticket number.

I need to export the ticket number to fire another module. Is there a way to get that ticket number outside of this area? I am stumped.

Thanks in advance.

options.path += orderNumber;
var req = https.request(options, function (res) {
  var chunks = [];

  res.on("data", function (chunk) {
    chunks.push(chunk);
  });

  res.on("end", function () {
    global.body = Buffer.concat(chunks);
    module.exports.cw = JSON.parse(body.toString()).customerOrderNo.replace(/\D/g,'');
    **console.log(module.exports.cw);**
  });  
});
**console.log(module.exports.cw);**
req.write(JSON.stringify({ id: 0,
  description: 'maxLength = 100',
  url: 'Sample string',
  objectId: 0,
  type: 'Sample string',
  level: 'Sample string',
  memberId: 0,
  inactiveFlag: 'false' }));
req.end();

Possible duplicate of [Why is my variable unaltered after I modify it inside of a function? - Asynchronous code reference](https://stackoverflow.com/questions/23667086/why-is-my-variable-unaltered-after-i-modify-it-inside-of-a-function-asynchron) — Patrick Roberts, Sep 25 '18 at 05:33
"Is there a way to get that ticket number outside of this area?" - No. "I need to export the ticket number to fire another module." - What do you mean, _fire another module_? — Amadan, Sep 25 '18 at 05:46

Shubham Gupta · Answer 1 · 2018-09-25T08:17:50.057

I think it is problem of scoping. Take a look at below code where we have moved export to bottom of module.

options.path += orderNumber;
var ticketNumber;
var req = https.request(options, function (res) {
  var chunks = [];

  res.on("data", function (chunk) {
    chunks.push(chunk);
  });

  res.on("end", function () {
    global.body = Buffer.concat(chunks);
    ticketNumber = JSON.parse(body.toString()).customerOrderNo.replace(/\D/g,'');
    **console.log(ticketNumber);**
  });  
});
**console.log(ticketNumber);**
req.write(JSON.stringify({ id: 0,
  description: 'maxLength = 100',
  url: 'Sample string',
  objectId: 0,
  type: 'Sample string',
  level: 'Sample string',
  memberId: 0,
  inactiveFlag: 'false' }));
req.end();

module.exports.getCw = function(){return ticketNumber}

`module.exports.cw = ticketNumber;` will set `module.exports.cw` = `undefined`, you can change it to `module.exports.getCw = function(){return ticketNumber}` to get it. — hong4rc, Sep 25 '18 at 07:55

score 0 · Answer 2 · answered Sep 25 '18 at 07:49

You can change first console.log(module.exports.cw); to console.log(1, module.exports.cw); and console.log(module.exports.cw); to console.log(2, module.exports.cw);

Your console will log :

2, undefined
1, <something>

When you call https.request, it request to url and get data, and need time to end it (call function of res.on("end", <this callback>))

While you request, Node.js call line after http.request : console.log(module.exports.cw);, but now call back inside https.request wasn't call (need time to request and call) so module.exports.cw is undefined

You should change req.write to call back of your https.request

Why is node.js module.export not returning globally?

2 Answers2