Why do variable in an inner function return nan when there is the same variable name at the inner function...
Contours of a clandestine nature
What was the first Unix version to run on a microcomputer?
How did the Bene Gesserit know how to make a Kwisatz Haderach?
How do we know the LHC results are robust?
Complex fractions
Sending manuscript to multiple publishers
What is the result of assigning to std::vector<T>::begin()?
Why do variable in an inner function return nan when there is the same variable name at the inner function declared after log
Novel about a guy who is possessed by the divine essence and the world ends?
If the heap is initialized for security, then why is the stack uninitialized?
Why does standard notation not preserve intervals (visually)
Is it my responsibility to learn a new technology in my own time my employer wants to implement?
Is it professional to write unrelated content in an almost-empty email?
Why don't programming languages automatically manage the synchronous/asynchronous problem?
What does convergence in distribution "in the Gromov–Hausdorff" sense mean?
Is there a difference between "Fahrstuhl" and "Aufzug"
Why do we use the plural of movies in this phrase "We went to the movies last night."?
Indicator light circuit
If Nick Fury and Coulson already knew about aliens (Kree and Skrull) why did they wait until Thor's appearance to start making weapons?
sp_blitzCache results Memory grants
If/When UK leaves the EU, can a future goverment conduct a referendum to join the EU?
Would a galaxy be visible from outside, but nearby?
How to invert MapIndexed on a ragged structure? How to construct a tree from rules?
Can I run my washing machine drain line into a condensate pump so it drains better?
Why do variable in an inner function return nan when there is the same variable name at the inner function declared after log
The Next CEO of Stack OverflowWhat is the naming convention in Python for variable and function names?How to execute a JavaScript function when I have its name as a stringWhat is a practical use for a closure in JavaScript?Javascript by reference vs. by valueWhy aren't ◎ܫ◎ and ☺ valid JavaScript variable names?What is the explanation for these bizarre JavaScript behaviours mentioned in the 'Wat' talk for CodeMash 2012?Is the recommendation to include CSS before JavaScript invalid?variable not writable in inner functionjavascript variable returning NaNFunction returns NaN when it shouldn't
What's happening here? I get a different result if I declare a variable after console.log in the inner function
I understand that var has a functional scope and inner function can access the variable from their parent
function outer() {
var a = 2;
function inner() {
a++;
console.log(a) //log NaN
var a = 8
}
inner()
}
outer()function outer() {
var a = 2;
function inner() {
a++;
console.log(a) //log 3
var b = 8
}
inner()
}
outer()The log returns NaN in the first example and log 3 in the second example
javascript function
edited 34 mins ago
Nick Parsons
10.3k2926
asked 43 mins ago
ClaudeClaude
426
add a comment |
What's happening here? I get a different result if I declare a variable after console.log in the inner function
I understand that var has a functional scope and inner function can access the variable from their parent
function outer() {
var a = 2;
function inner() {
a++;
console.log(a) //log NaN
var a = 8
}
inner()
}
outer()function outer() {
var a = 2;
function inner() {
a++;
console.log(a) //log 3
var b = 8
}
inner()
}
outer()The log returns NaN in the first example and log 3 in the second example
javascript function
edited 34 mins ago
Nick Parsons
10.3k2926
asked 43 mins ago
ClaudeClaude
426
add a comment |
What's happening here? I get a different result if I declare a variable after console.log in the inner function
I understand that var has a functional scope and inner function can access the variable from their parent
function outer() {
var a = 2;
function inner() {
a++;
console.log(a) //log NaN
var a = 8
}
inner()
}
outer()function outer() {
var a = 2;
function inner() {
a++;
console.log(a) //log 3
var b = 8
}
inner()
}
outer()The log returns NaN in the first example and log 3 in the second example
javascript function
edited 34 mins ago
Nick Parsons
10.3k2926
asked 43 mins ago
ClaudeClaude
426
What's happening here? I get a different result if I declare a variable after console.log in the inner function
I understand that var has a functional scope and inner function can access the variable from their parent
function outer() {
var a = 2;
function inner() {
a++;
console.log(a) //log NaN
var a = 8
}
inner()
}
outer()function outer() {
var a = 2;
function inner() {
a++;
console.log(a) //log 3
var b = 8
}
inner()
}
outer()The log returns NaN in the first example and log 3 in the second example
function outer() {
var a = 2;
function inner() {
a++;
console.log(a) //log NaN
var a = 8
}
inner()
}
outer()function outer() {
var a = 2;
function inner() {
a++;
console.log(a) //log NaN
var a = 8
}
inner()
}
outer()function outer() {
var a = 2;
function inner() {
a++;
console.log(a) //log 3
var b = 8
}
inner()
}
outer()function outer() {
var a = 2;
function inner() {
a++;
console.log(a) //log 3
var b = 8
}
inner()
}
outer()javascript function
javascript function
edited 34 mins ago
Nick Parsons
10.3k2926
asked 43 mins ago
ClaudeClaude
426
edited 34 mins ago
Nick Parsons
10.3k2926
asked 43 mins ago
ClaudeClaude
426
edited 34 mins ago
Nick Parsons
10.3k2926
edited 34 mins ago
Nick Parsons
10.3k2926
edited 34 mins ago
Nick Parsons
10.3k2926
10.3k2926
asked 43 mins ago
ClaudeClaude
426
asked 43 mins ago
ClaudeClaude
426
asked 43 mins ago
ClaudeClaude
426
426
add a comment |
add a comment |
3 Answers
3
active
oldest
votes
This is due to hoisting
The declaration of a in the inner function is hoisted to the top of the function, overriding the outer function's a, so a is undefined
undefined++ returns NaN, hence your result.
Your code is equivalent to:
function outer() {
var a=2;
function inner() {
var a;
a++;
console.log(a); //log NaN
a = 8;
}
inner();
}
outer();
Rewriting your code in this way makes it easy to see what's going on.
edited 24 mins ago
Shidersz
9,3112933
answered 37 mins ago
jrojro
562113
add a comment |
Because var is hoisted through the function, you're essentially running undefined++ which is NaN. If you remove var a = 8 in inner, the code works as expected:
function outer() {
var a = 2;
function inner() {
a++;
console.log(a);
}
inner();
}
outer();answered 34 mins ago
Jack BashfordJack Bashford
13.8k31848
add a comment |
var a=0;
function outer(){
a=2;
function inner(){
a=a+1;
console.log(a)
a = 8
}
inner()
}
outer()
answered 34 mins ago
Darshit ShahDarshit Shah
53
3
How does this piece of code explains the issue? Can you provide an explanation of the code you have posted?
– Shidersz
27 mins ago
They can’t access the inner function value so we have to defined globally. After globally you can use A value anywhere in the code
– Darshit Shah
25 mins ago
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f55428371%2fwhy-do-variable-in-an-inner-function-return-nan-when-there-is-the-same-variable%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
This is due to hoisting
The declaration of a in the inner function is hoisted to the top of the function, overriding the outer function's a, so a is undefined
undefined++ returns NaN, hence your result.
Your code is equivalent to:
function outer() {
var a=2;
function inner() {
var a;
a++;
console.log(a); //log NaN
a = 8;
}
inner();
}
outer();
Rewriting your code in this way makes it easy to see what's going on.
edited 24 mins ago
Shidersz
9,3112933
answered 37 mins ago
jrojro
562113
add a comment |
This is due to hoisting
The declaration of a in the inner function is hoisted to the top of the function, overriding the outer function's a, so a is undefined
undefined++ returns NaN, hence your result.
Your code is equivalent to:
function outer() {
var a=2;
function inner() {
var a;
a++;
console.log(a); //log NaN
a = 8;
}
inner();
}
outer();
Rewriting your code in this way makes it easy to see what's going on.
edited 24 mins ago
Shidersz
9,3112933
answered 37 mins ago
jrojro
562113
add a comment |
This is due to hoisting
The declaration of a in the inner function is hoisted to the top of the function, overriding the outer function's a, so a is undefined
undefined++ returns NaN, hence your result.
Your code is equivalent to:
function outer() {
var a=2;
function inner() {
var a;
a++;
console.log(a); //log NaN
a = 8;
}
inner();
}
outer();
Rewriting your code in this way makes it easy to see what's going on.
edited 24 mins ago
Shidersz
9,3112933
answered 37 mins ago
jrojro
562113
This is due to hoisting
The declaration of a in the inner function is hoisted to the top of the function, overriding the outer function's a, so a is undefined
undefined++ returns NaN, hence your result.
Your code is equivalent to:
function outer() {
var a=2;
function inner() {
var a;
a++;
console.log(a); //log NaN
a = 8;
}
inner();
}
outer();
Rewriting your code in this way makes it easy to see what's going on.
edited 24 mins ago
Shidersz
9,3112933
answered 37 mins ago
jrojro
562113
edited 24 mins ago
Shidersz
9,3112933
edited 24 mins ago
Shidersz
9,3112933
edited 24 mins ago
Shidersz
9,3112933
9,3112933
answered 37 mins ago
jrojro
562113
answered 37 mins ago
jrojro
562113
answered 37 mins ago
jrojro
562113
562113
add a comment |
add a comment |
Because var is hoisted through the function, you're essentially running undefined++ which is NaN. If you remove var a = 8 in inner, the code works as expected:
function outer() {
var a = 2;
function inner() {
a++;
console.log(a);
}
inner();
}
outer();answered 34 mins ago
Jack BashfordJack Bashford
13.8k31848
add a comment |
Because var is hoisted through the function, you're essentially running undefined++ which is NaN. If you remove var a = 8 in inner, the code works as expected:
function outer() {
var a = 2;
function inner() {
a++;
console.log(a);
}
inner();
}
outer();answered 34 mins ago
Jack BashfordJack Bashford
13.8k31848
add a comment |
Because var is hoisted through the function, you're essentially running undefined++ which is NaN. If you remove var a = 8 in inner, the code works as expected:
function outer() {
var a = 2;
function inner() {
a++;
console.log(a);
}
inner();
}
outer();answered 34 mins ago
Jack BashfordJack Bashford
13.8k31848
Because var is hoisted through the function, you're essentially running undefined++ which is NaN. If you remove var a = 8 in inner, the code works as expected:
function outer() {
var a = 2;
function inner() {
a++;
console.log(a);
}
inner();
}
outer();function outer() {
var a = 2;
function inner() {
a++;
console.log(a);
}
inner();
}
outer();function outer() {
var a = 2;
function inner() {
a++;
console.log(a);
}
inner();
}
outer();answered 34 mins ago
Jack BashfordJack Bashford
13.8k31848
answered 34 mins ago
Jack BashfordJack Bashford
13.8k31848
answered 34 mins ago
Jack BashfordJack Bashford
13.8k31848
answered 34 mins ago
Jack BashfordJack Bashford
13.8k31848
13.8k31848
add a comment |
add a comment |
var a=0;
function outer(){
a=2;
function inner(){
a=a+1;
console.log(a)
a = 8
}
inner()
}
outer()
answered 34 mins ago
Darshit ShahDarshit Shah
53
3
How does this piece of code explains the issue? Can you provide an explanation of the code you have posted?
– Shidersz
27 mins ago
They can’t access the inner function value so we have to defined globally. After globally you can use A value anywhere in the code
– Darshit Shah
25 mins ago
add a comment |
var a=0;
function outer(){
a=2;
function inner(){
a=a+1;
console.log(a)
a = 8
}
inner()
}
outer()
answered 34 mins ago
Darshit ShahDarshit Shah
53
3
How does this piece of code explains the issue? Can you provide an explanation of the code you have posted?
– Shidersz
27 mins ago
They can’t access the inner function value so we have to defined globally. After globally you can use A value anywhere in the code
– Darshit Shah
25 mins ago
add a comment |
var a=0;
function outer(){
a=2;
function inner(){
a=a+1;
console.log(a)
a = 8
}
inner()
}
outer()
answered 34 mins ago
Darshit ShahDarshit Shah
53
var a=0;
function outer(){
a=2;
function inner(){
a=a+1;
console.log(a)
a = 8
}
inner()
}
outer()
answered 34 mins ago
Darshit ShahDarshit Shah
53
answered 34 mins ago
Darshit ShahDarshit Shah
53
answered 34 mins ago
Darshit ShahDarshit Shah
53
answered 34 mins ago
Darshit ShahDarshit Shah
53
53
3
How does this piece of code explains the issue? Can you provide an explanation of the code you have posted?
– Shidersz
27 mins ago
They can’t access the inner function value so we have to defined globally. After globally you can use A value anywhere in the code
– Darshit Shah
25 mins ago
add a comment |
3
How does this piece of code explains the issue? Can you provide an explanation of the code you have posted?
– Shidersz
27 mins ago
They can’t access the inner function value so we have to defined globally. After globally you can use A value anywhere in the code
– Darshit Shah
25 mins ago
3
3
How does this piece of code explains the issue? Can you provide an explanation of the code you have posted?
– Shidersz
27 mins ago
How does this piece of code explains the issue? Can you provide an explanation of the code you have posted?
– Shidersz
27 mins ago
They can’t access the inner function value so we have to defined globally. After globally you can use A value anywhere in the code
– Darshit Shah
25 mins ago
They can’t access the inner function value so we have to defined globally. After globally you can use A value anywhere in the code
– Darshit Shah
25 mins ago
add a comment |
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f55428371%2fwhy-do-variable-in-an-inner-function-return-nan-when-there-is-the-same-variable%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
