Questions tagged [function-expression]
100 questions
1
vote
1 answer
Why does the "typeof" of a named function expression return undefined?
I'm new to JS, so please forgive me if this sounds stupid. I was playing with the concepts of function declaration and function expression.
I have the following code:
var printSomething = function printSomeString(string) {
…
Auro
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1
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1 answer
Runnable class is not exectued
I implemented a virtual counter, just counting up and down between 0-100.
It's very Simple, the factory supplies a VirtualCounter which implements Runnable.
@Getter
@Setter
public class VirtualTimer implements Runnable {
private int…
Anna Klein
- 1,906
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1
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0 answers
Why can i invoke a variable in JavaScript as a function due to the Function Expression variety?
const result = (numberOne, numberTwo) =>
{
if(numberOne > numberTwo){
return true;
} else {
return false;
}
};
console.log(result(1, 2)); // here i use the variable as a function?!
So why can i use a variable as a…
BitFlippa
- 51
- 5
1
vote
0 answers
What exactly is a function expression in Javascript?
So I found this terminology a little bit confusing. I normally see tutorials talking about function expression with an variable assigned to a function, but also, from Mozilla's official website function expression, it says:
A function expression is…
Hang Chen
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1
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1 answer
Difficulties with using function expression
Hopefully you will answer it !
var myform = document.getElementById("myform"),
saveBtn = document.getElementById("submit");
saveBtn.addEventListener("click", saveInfo);
var saveInfo = function (e){
e.preventDefault();
var dateValue =…
janaravi
- 106
- 1
- 8
1
vote
3 answers
Struggling to Understand the Parameter Content when using .map on Function Expressions
So I'm looking at function expressions.
This is the code I'm playing with:
var modifiedNames = [ "Thomas Meeks",
"Gregg Pollack",
"Christine Wong",
"Dan McGaw"…
phurst-so
- 386
- 5
- 15
1
vote
2 answers
Is it possible to have parameters for anonymous function?
Given
var stuffs = [
{ id : 1, name : "orange"},
{ id : 2, name : "apple"},
{ id : 0, name:"grapes"}
];
var filterMethod1 = new function(o){return (o.id>=1);}; // this gives undefined error for o
function filterMethod2(o) {return…
rustyengineer
- 343
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- 16
1
vote
2 answers
function declaration and function expression performance difference
I have used JSperf to test a small sample of code.
According to a few articles I came across, both should have similar performance with test2 having a little edge. But here it's the complete opposite. Can someone explain why the huge…
Pardha.Saradhi
- 468
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- 27
1
vote
1 answer
Can isNaN be used as identifier in a named function expression?
The context:
I am reading the book You Don't Know JS: Up & Going, Chapter 2: Into JavaScript. In the Polyfilling section, the author gives the following example:
if (!Number.isNaN) {
Number.isNaN = function isNaN(x) {
return x !== x;
…
user3723667
- 41
- 8
1
vote
2 answers
for loop assigns same functon everytime in Livescript
I would expect "x's" results, "y's" results and "z's" results be the same:
In Livescript:
x =
a: -> 3
b: -> 4
y = {}
for k, v of x
console.log "key: ", k, "val: ", v
y[k] = -> v.call this
console.log "y is: ", y
console.log "x's:…
ceremcem
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1
vote
1 answer
Anonymous function expression in Google Chrome
I am using Google Chrome version 52 64-bit.
I found out that if I use anonymous function expression ex.
// Anonymous function expression
var expressionFunc = function(){
return true;
};
The variable expressionFunc will hold the assigned…
RuvenGam
- 64
- 1
- 9
1
vote
2 answers
Function expression in JavaScript confusion
I'm trying to make sense of this code from another developer and my JavaScript knowledge is lacking. This function is supposed to take the header menu of a site and convert it into a mobile style menu.
I understand why jQuery is being passed in as…
Anne Lee
- 107
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1
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0 answers
In JavaScript, Why function expression needs to be in bracket for calling the function
I tried calling
function(v){alert(""+v);}(4);
But warning came out
function statement requires a name
When I called using name
function fname(v){alert(""+v);}(4);
Nothing happenedBut when I called using…
Rahul Jain
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1
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1 answer
What are good situations to use function expression instead of function declaration?
I will prefer to use function declaration all the time because I can place the function anywhere on the source file. If I use function expression, the function has to be placed at the top of the source file.
Are there good situations to use function…
guagay_wk
- 26,337
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1
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3 answers
Javascript private methods: function expression vs function declaration
A common method of creating private methods (of sorts) in javascript is this:
Class = function (arg0, arg1) {
var private_member = 0;
var privateMethod = function () {
return private_member;
};
}
The above example could also…
Wingblade
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