Read/Use variables from another javascript file

Question

If I import a js file like this :

const importedFile = require( './file1');

I can see all my functions and console logs of file1 running, but I can't run or use a specific variable

If I console.log( importedFile ) I get this : {} empty object !

How to get all variables from file1.js ?

Have a read about it here: developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… — StudioTime
– StudioTime, Commented Dec 9, 2019 at 11:21
@DarrenSweeney — That's ES6 imports, not the Node module system. — Quentin
– Quentin, Commented Dec 9, 2019 at 11:23
From that link I tried this: import * as importedFile from './file1.js'; Gives me this: SyntaxError: Unexpected token * — itneg
– itneg, Commented Dec 9, 2019 at 11:29

Quentin · Accepted Answer · 2019-12-09 11:21:45Z

2

JavaScript modules are self-contained environments with their own scope.

Only explicitly exported values are available outside of the module.

So, if you want something in ./file1 to be available in importedFile, then you need to include it in the exports:

const value = "Hello, world";

function thisIsAFunction() {
    console.log(value);
}

module.exports = {
    thisIsAFunction
}

Then you can:

const importedFile = require( './file1');
importedFile.thisIsAFunction();

answered Dec 9, 2019 at 11:21

Quentin

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9 Comments

itneg Over a year ago

Yes I was able to import one variable, but as I said I can see everything running, but I can't use anything, why is that? Is there any way to export all variables ?

Quentin Over a year ago

No. You can't export variables, only values.

itneg Over a year ago

Yeah all variable values, all together, not just one. And another problem is that in file1 my variables values change every 10 secs, but when I try to import I get only the first value

Quentin Over a year ago

As I said, you can only export values, not variables. You can export a function that gives you their current values on demand. And you can put as many values in the object you export as you like.

itneg Over a year ago

Ah okay, but if the ' const value = "Hello, world"; ' was declared inside the function, how to read it then? Cause I need to read/use not just console.log it

|

itneg · Accepted Answer · 2019-12-09 12:19:58Z

0

I figured it out, in file1 I can export variables like this :

function thisIsAFunction() {
    let var1 = { qty: 123 }
    let var2 = { qty: 123 }
    let var3 = { qty: 123 }

    return [ var1, var2, var3 ];
}
module.exports = {
    thisIsAFunction
}

Then read/use the first variable like this:

let importedValue= importedFunct.thisIsAFunction()

console.log(  importedValue[0][0].qty)

answered Dec 9, 2019 at 12:19

itneg

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