CODEWITHSUNDEEP
javascriptvariables
AzDeveloper
AzDeveloper

Reputation: 341

Define a unchangeable variable

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)

Upvotes: 1

Views: 761

Answers (2)

T.J. Crowder
T.J. Crowder

Reputation: 1074445

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;
}

Upvotes: 3

Jamiec
Jamiec

Reputation: 136114

Your code already does exactly what you describe. A small change is required to make bar accessible outside of the function where it is initialized, but if you wait 6 seconds you'll see the result you expected in the example below.

var foo = 0;
var bar;
setInterval(function(){foo++}, 1000);
setTimeout(function(){bar = foo}, 4000) //bar = 4;
setTimeout(function(){
    console.log(foo,bar)
}, 6000)

Upvotes: 3

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