1.
function abc(){
alert("named function");
}
v/s
2.
function(){
alert("Un-Named function");
}
Kindly explain from beginners point.
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2The one with a name can be referenced by that name. The one without a name can't, it's "anonymous." Functionally they're identical.David– David2013-09-16 13:10:06 +00:00Commented Sep 16, 2013 at 13:10
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Just try to call the function in your second example.Bart– Bart2013-09-16 13:12:08 +00:00Commented Sep 16, 2013 at 13:12
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1The second one is invalid syntax, and the code will throw a SyntaxError. To be used without a name, it will require evaluation within some expression.user2736012– user27360122013-09-16 13:18:05 +00:00Commented Sep 16, 2013 at 13:18
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1Up-vote + Thank you for askingAlison– Alison2016-12-02 14:33:01 +00:00Commented Dec 2, 2016 at 14:33
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what about this one: setTimeout (() => {}, time) ????aleXela– aleXela2017-11-27 21:11:22 +00:00Commented Nov 27, 2017 at 21:11
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2 Answers
They work exactly the same. It's only in how you are able to run them that they are different.
So example #1 you could call again at any point with abc();. For example 2, you would either have to pass it as a parameter to another function, or set a variable to store it, like this:
var someFunction = function() {
alert("Un-Named function");
}
Here's how to pass it into another function and run it.
// define it
function iRunOtherFunctions(otherFunction) {
otherFunction.call(this);
}
// run it
iRunOtherFunctions(function() {
alert("I'm inside another function");
});
As David mentions below, you can instantly call it too:
(function() {
alert("Called immediately");
})(); // note the () after the function.
9 Comments
David
For completeness, another option for the anonymous function is to immediately call (or self-call) it:
(function() { alert('something'); })();
Jordan
Added more examples. Thanks David.
canon
@Jordan, your last example needs to wrap the function like
(function(){})(); or (function(){}());.Jordan
@user2736012 not sure what you're talking about. The 2nd example works fine. I've already fixed the missing wrapped parens on the last example.
user2736012
@Jordan: I was talking about the second example in the question. It's not valid syntax as shown. And then I was talking about your last example. You fixed it after my and cannon's comment.
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Both can be used to achieve the same but the main difference is the anonymous functions don't need a name. Anonymous functions are functions that are dynamically declared at runtime. They’re called anonymous functions because they aren’t given a name in the same way as normal functions.
Please refer this link