NodeJs require('./file.js') issues

Question

I am having issues including files to execute in my NodeJs project.

I have two files in the same directory:

a.js

var test = "Hello World";

and

b.js

require('./a.js');
console.log(test);

I execute b.js with node b.js and get the error ReferenceError: test is not defined.

I have looked through the docs http://nodejs.org/api/modules.html#modules_file_modules

What am I missing?

FYI declaring a "var" or "let" like on a.js doesn't mean that it's accessible Globally (with require), but only inside the file a.js — Bill, May 30 '19 at 09:42

score 100 · Accepted Answer · answered Jul 30 '12 at 17:35

100

Change a.js to export the variable:

exports.test = "Hello World";

and assign the return value of require('./a.js') to a variable:

var a = require('./a.js');
console.log(a.test);

Another pattern you will often see and probably use is to assign something (an object, function) to the module.exports object in a.js, like so:

module.exports = { big: "string" };

answered Jul 30 '12 at 17:35

rdrey

9,379
4
40
52

3

can we still use this js file (a.js) in html ? – 0x016F2818 Mar 22 '16 at 07:06
To be able to use it in html you should 1) code it to work as in html ; 2) export the needed functions, variables so it also work in node. – Hugo LOPEZ Sep 21 '18 at 09:55

score 23 · Answer 2 · answered Jul 30 '12 at 17:35

You are misunderstanding what should be happening. The variables defined in your module are not shared. NodeJS scopes them.

You have to return it with module.exports.

a.js

module.exports = "Hello World";

b.js

var test = require('./a.js');
console.log(test);

score 1 · Answer 3 · answered Apr 08 '17 at 21:31

if you want to export the variable in another file.There are two patterns. One is a.js
global.test = "Hello World"; //test here is global variable,but it will be polluted

The other is
a.js module.exports.test = "Hello World"; or exports.test= "Hello World"; b.js var test = require('./a.js'); //test in b.js can get the test in a.js console.log(test);

NodeJs require('./file.js') issues

3 Answers3

Linked