Jquery : undefined is not a function

Question

I have a code below and when i try to run get the error when i call the function . I wonder hey this his happening ? help plz ...

jQuery(document).ready(function($) {
        //load config file 
        $.getScript(baseURl+"/wsj/wconf.js", function(data, textStatus, jqxhr) {
            console.log(data); // it is ok 

                jq();  // Uncaught TypeError: undefined is not a function 
                //_cusApp.ini();  //Uncaught TypeError: Cannot call method 'ini' of undefined 

                var _cusApp = {
                        ini: function (inc) {
                            console.log('ini'); 
                        },
                };

                var jq = function ( ){
                    $(document).height(); // jquery not availble here   
                }
        }); 

    });

I think there are confliction with other jQuery. Please check this — Prashant Parekh, Aug 09 '13 at 11:25

score 6 · Answer 1 · edited Jun 20 '20 at 09:12

6

It's about invoking jq() function before it's declared.

jq is undefined, because it's not declared yet...!

Update (@David Barker suggestion)

The whole code would work if a named function would be declared instead of an anonymous one.

As an anonymous function is created during run-time, it's not available until the assignment is executed.

In opposite, as a named function is declared in parse time, it's available to the code even if it's declared after invoking it.

Example of anonymous function

myFunction(); // Wrong, it's undefined!

var myFunction = function() {};

myFunction(); // OK, now is declared and it can be invoked

Example of named function

myFunction(); // As the function has been already parsed, it is available!

function myFunction() {};

myFunction(); // OK!

edited Jun 20 '20 at 09:12

Community

1
1

answered Aug 09 '13 at 11:26

Matías Fidemraizer

63,804
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maybe some clarification on why `var jq = function() {...}` and `function jq() {...}` differ would give the op some clarity? +1 though as this is the answer. – David Barker Aug 09 '13 at 11:28
@Blender Sometimes a downvote isn't the best option. I thought I was right and that's why I updated the question. I've removed the whole update because you're right. Keep calm! – Matías Fidemraizer Aug 09 '13 at 11:40
@Blender Why you removed your comment?! – Matías Fidemraizer Aug 09 '13 at 11:43
@MatiaFidemraizer spot on :-) – David Barker Aug 09 '13 at 12:02

Arun P Johny · Answer 2 · 2013-08-09T11:31:38.290

3

it should be

jQuery(function($) {
    //load config file 
    $.getScript(baseURl+"/wsj/wconf.js", function(data, textStatus, jqxhr) {
        console.log(data); // it is ok 

        //these two variable declaration shoule happen before their usage
        var _cusApp = {
            ini: function (inc) {
                console.log('ini'); 
            },
        };

        var jq = function ( ){
            $(document).height(); // jquery not availble here   
        }

        jq();
        _cusApp.ini();
    }); 

});

edited Aug 09 '13 at 11:31

answered Aug 09 '13 at 11:25

Arun P Johny

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Unless he's running in `strict` `jq` should be hoisted, so I don't see what this fixes. – André Dion Aug 09 '13 at 11:26
3

@AndréDion no, a function expression will no get hoisted, declaration will get hoisted – Arun P Johny Aug 09 '13 at 11:27
@AndréDion see function expression error http://jsfiddle.net/arunpjohny/YPQMt/1/ and declaration http://jsfiddle.net/arunpjohny/YPQMt/2/ – Arun P Johny Aug 09 '13 at 11:28
@RoryMcCrossan mostly by AndréDion from his comment – Arun P Johny Aug 09 '13 at 11:31
@AndréDion http://www.adequatelygood.com/JavaScript-Scoping-and-Hoisting.html would be a good read – Arun P Johny Aug 09 '13 at 11:32
I didn't downvote you, sorry. I removed my answer and upvoted your comment correcting me. – André Dion Aug 09 '13 at 11:33

score 0 · Answer 3 · answered Aug 09 '13 at 13:07

0

First you declare a function and then call her because javascript read line by line one after the other, when you call the function jq () it still had not been declared ..

'sorry for my english'

answered Aug 09 '13 at 13:07

Jquery : undefined is not a function

3 Answers3

Update (@David Barker suggestion)

Example of anonymous function

Example of named function