关于 JavaScript 中变量的快速菜鸟问题

Question

Stupid question, but if I have code like this:

var x;
var y;
var z = x + y;

And then through the program I update the variables for x and y, but when I use the console to check var z, it gives me NaN. So the program is doing that calculation once at the beginning and not updating Z as it continues. So what's the solution to keep checking Z for the variable changes? Do I have to do a loop with setInterval to keep checking the new updated Z variable? Thanks

Answer 1

Yeah, your comment is right. JavaScript doesn't provide a way to create a live binging.

So what's the solution to keep checking Z for the variable changes?

All depends on what you are trying to do.

Answer 2

What you think about the code:

var x = 1;
var y = 2;
var z = x + y;
console.log("The value of z variable: ", z);

PS. Preferably you should use let :

let x = 1;
let y = 2;
let z = x + y;
console.log("The value of z variable: ", z);