Define a unchangeable variable

Question

I have this code here:

var foo = 0;

setInterval(function(){foo++}, 1000);

This will increase

foo

by 1 every second. Is there any way to define a

bar

variable which will be the

foo

variable at that time and not changing?
It sounds confusing, so here:
For example:

var foo = 0;

setInterval(function(){foo++}, 1000);

setTimeout(function(){var bar = foo}, 4000) //bar = 4;

Is there anyway to keep

bar

at 4 and not increasing with

foo

? Thanks a lot!

(Sorry for bad English)

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Answer 1

If you mean you want bar to be available in the same scope as foo, just move its declaration:

var foo = 0;
var bar;
setInterval(function() {
    foo++;
}, 1000);
setTimeout(function() {
    bar = foo;
}, 4000);

Once it gets that value assigned by the timer, it won't change again (unless you change it somewhere).

Live Example:

var foo = 0;
var bar;
setInterval(function() {
    foo++;
}, 1000);
setTimeout(function() {
    bar = foo;
}, 4000);
var stop = Date.now() + 10000;
var timer = setInterval(function() {
    console.log("foo = " + foo + ", bar = " + bar);
    if (Date.now() > stop) {
        clearInterval(timer);
    }
}, 1000);

.as-console-wrapper {
  max-height: 100% !important;
}

Define a unchangeable variable

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