在回调中访问全局定义的变量？

Question

I am writing a three.js application and need to access a variable called camera , because whenever I click a button I want to move the camera up and down.

However, my buttons are nested callbacks and I am wondering how can I accessing the variable within the callbacks?

eg

    let camera = ...
    let circles = document.querySelectorAll('circle');
    circles.forEach(function(c){
        c.onclick = function(e){
            circles.forEach(function(circle){
                circle.classList.remove('active');
                circle.classList.add('disabled');
            });
            e.target.classList.add('active');
            e.target.classList.remove('disabled');
            if (e.target.id === "example"){
                camera.position.set(0,0,0) //camera not defined
            }
            debugger;
        }
    });

I am a little confused why I can access the circles varaible at the debugger point, however it keeps saying camera is undefined.

Answer 1

Just guessing, maybe because it's not used it got optimized away? Try to do something with camera, print its name or whatever. Then see if it's available in debug.

Answer 2

you can't access let variable inside. visit below URL it'll help.

https://stackoverflow.com/a/58735690/10627591

If you want to access that variable declared it var keyword.

Answer 3

Ok, I am at a loss for words.

If I try to use the variable, eg camera.position.set(0,0,0) inside where I want to use it, I can print the variable inside the console.

If I do not use it, then I get an error.

The problem was me trying to debug and write tests first, before actually writing it.