This question already has answers here:
JavaScript closure inside loops – simple practical example
(44 answers)
Closed 5 years ago.
for(i = 0; i < 10; i++){
setTimeOut(function(){
console.log(i);
},2000);
}
When I execute this, its printing 10, 10 times instead of 1,2,3....10. How do I fix this
You need to modify your code like this
function print(i){
console.log(i);
}
for(i=0;i<10;i++){
setTimeout(print.bind(null,i),2000);
}
Related
This question already has answers here:
setTimeout calls function immediately instead of after delay
(2 answers)
JavaScript setTimeout() won't wait to Execute? [duplicate]
(3 answers)
setTimeout in for-loop does not print consecutive values [duplicate]
(10 answers)
JavaScript closure inside loops – simple practical example
(44 answers)
Closed 4 years ago.
can someone help me understanding why this code:
for (var i =0; i < 2; i++) {
setTimeout(console.log(i), 0);
}
console.log("aaa");
Will write:
0
1
aaa
But that code:
for (var i =0; i < 2; i++) {
setTimeout(function(){console.log(i)}, 0);
}
console.log("aaa");
Will wirte that:
aaa
2
2
Note that I understand how the second vers. work, I don't get why the first one make it differnt.
Thanks!
This question already has answers here:
JavaScript closure inside loops – simple practical example
(44 answers)
let keyword in the for loop
(3 answers)
Closed 4 years ago.
Why output is 10 when use var and with let it works the loop.
Edit the output is 11 but why let and var are different
var funcions = [];
for (var x = 0; x <= 10; x++) {
funcions.push(function() {
console.log(x);
});
}
funcions.forEach(
function(func) {
func();
}
);
I know that let, is a signal that the variable may be reassigned, such as a counter in a loop, or a value swap in an algorithm. It also signals that the variable will be used only in the block it’s defined in, which is not always the entire containing function.
This question already has answers here:
JavaScript closure inside loops – simple practical example
(44 answers)
Is setTimeout with no delay the same as executing the function instantly?
(4 answers)
Closed 5 years ago.
when I print "i" inside setTimeout with time diff 0. why does it print "n" the same number always?
for(i = 0; i < 5; i++) {
setTimeout(function() {console.log(i)}, 0);
}
Output:
5
5
5
5
5
This question already has answers here:
JavaScript closure inside loops – simple practical example
(44 answers)
How do JavaScript closures work?
(86 answers)
Closed 5 years ago.
I understand closures but I don't understand how this example works:
for (var i=1; i<=5; i++) {
setTimeout( function timer(){
console.log( i );
}, i*1000 );
}
In this example it logs 6 six times with a value of six. I understand this is due to closures. However, I don't understand how. Any help would be appreciated.
This question already has answers here:
setTimeout in for-loop does not print consecutive values [duplicate]
(10 answers)
JavaScript closure inside loops – simple practical example
(44 answers)
Closed 8 years ago.
I'm new to asynchronous programming, and I'm having a hard time getting the concept.
Please help!!!
Ive come up with a simple example:
for (var i = 1; i <= 10; i++) {
setTimeout(function () {
console.log(i);
}, 1000);
}
All I want is to print the indexes in ascending order but due to asynchronous action forced by the setTimeout i'm getting the last index printed out 10 times.
I understand why this happens...
No matter what I've tried (I don't think my misunderstanding needs elaboration) I failed solving this stupid riddle...
Im obviously missing something basic.
Please help me figure it out.
It's because all those functions use the same variable i, which is equal to 10 during invocation of them. Try something like this:
for (var i = 1; i <= 10; i++) {
setTimeout((function (k) {
return function(){
console.log(k);
}
}(i)), 1000);
}
It's because JavaScript has closures. You can read about them here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Closures