Node.JS global variable declaring when local is same name

Question

I have this code:

let manager;
exports.setup = async manager => {
    this.manager = manager;
};

This is possible duplicate but every time I saw this, solution was to use window.manager = manager to set global variable from inside function. How to do this in Node.JS where is no window? this.manager not working, because its seems this.manager !== manager (the global one)

You can create Global objects in NodeJS https://nodejs.org/api/globals.html. But that is not really recommended like `global.myVar = 'someValue'` — Ankit Agarwal, Oct 22 '18 at 10:32
`let manager` creates a variable in the current scope, which is the module scope, not the global scope. — Quentin, Oct 22 '18 at 10:32
Do you mean [the global object](https://stackoverflow.com/questions/43627622/what-is-the-global-object-in-nodejs)? — VLAZ, Oct 22 '18 at 10:32
The real solution here is **Don't mask variables you want to access** — Quentin, Oct 22 '18 at 10:33
@Quentin I KNOOOW :D But I am perfectionalist what need it like that :D — Baterka, Oct 22 '18 at 10:36
@DavidBubeník `global.manager = manager;` should work but not recommended as @Quentin pointed out. — tbking, Oct 22 '18 at 10:40

mihai · Answer 1 · 2018-10-22T12:33:11.813

Your function parameter hides the local variable in this case.

Consider the following 2 modules:

lib.js

let manager = 2;
exports.setup = async manager => {
    this.manager = manager;
};

main.js

var v = require("./lib.js");
v.setup(5);
console.log(v.manager);

This prints 5 because manager is the parameter you pass to the function. If you want to obtain the value of the local manager (2 in this example) you need to change the name of the function parameter or remove it entirely.

let manager = 2;
exports.setup = async input => {
    this.manager = manager;
};

or

let manager = 2;
exports.setup = async () => {
    this.manager = manager;
};

Node.JS global variable declaring when local is same name

1 Answers1