CODEWITHSUNDEEP
javascriptanonymous-function
MegaNairda
MegaNairda

Reputation: 839

Why does this call to anonymous function does not work?

Why does this

$( '#someid' ).click( function() {
    getdata( 'listing' , function( data ) {
        showlist( data );
    }, 'string' , 1 );
});

work but this one doesn't

$( '#someid' ).click( function() {
    getdata( 'listing' , showlist( data ), 'string' , 1 );
});

Upvotes: 0

Views: 68

Answers (4)

Khanh TO
Khanh TO

Reputation: 48992

function( data ) {
        showlist( data );
    }

Means that you are passing in an anonymous function

showlist( data )

Means that you are calling showList(data) and pass the returned value to the function. In case you want to use your second case correctly, fix it like this:

$( '#someid' ).click( function() {
    getdata( 'listing' , showlist, 'string' , 1 );
});

Upvotes: 1

kamituel
kamituel

Reputation: 35970

In your second example, you are executing showlist(data) and putting its result value as a getdata() parameter.

You could imagine, that this:

getdata( 'listing' , showlist( data ), 'string' , 1 );

is a logical equivalent of this: 

var temp = showlist( data );
getdata( 'listing', temp, 'string', 1);

Upvotes: 1

Jon
Jon

Reputation: 437904

Because the first is passing a function as the second argument to getdata, while the second is passing the result of calling a function.

You could write the second correctly as 

$( '#someid' ).click( function() {
    getdata( 'listing' , showlist, 'string' , 1 );
});

We are no longer calling showlist here, rather allowing getdata to call it later on.

Upvotes: 0

Fabrizio Calderan
Fabrizio Calderan

Reputation: 123438

it doesn't work because getdata ask a function as a second parameter. In the second example you'are executing the function (and passing its returning value) instead of passing the function itself.

if you write

$( '#someid' ).click( function() {
    getdata( 'listing' , showlist, 'string' , 1 );
});

without parens () it still works, but as you can see, you can't pass anymore the data parameter along the function showlist

Upvotes: 1

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