CODEWITHSUNDEEP
javascriptundefined
James P. Wright
James P. Wright

Reputation: 9131

Function is undefined after being defined in Javascript

This jsFiddle highlights my issue.
It is mimicking some functionality I have where an Object is defined and sent to the Page via socket.io.

I have a setInterval function checking if Pots is a function, and when it is I fire an Event. During that Event I try to instantiate a new instance of Pots only to be told that it is undefined.

The code:

var Pots;

$(document).ready(function(){
    var timerId = 0;
    var otherTimer = 0;

    otherTimer = setInterval(function() { console.log("Creating"); Pots = function() {}; }, 5000);

    timerId = setInterval(function() {
        console.log("Checking");

        if (_.isFunction(Pots)) {
            console.log(Pots);
            clearInterval(timerId);
            clearInterval(otherTimer);

            var evt = document.createEvent('Event');
            evt.initEvent('ObjectsAvailable', true, true);
            document.dispatchEvent(evt);
        }

    }, 1000);

});

document.addEventListener('ObjectsAvailable', function(e) {
    console.log(Pots);
    var Pots = new Pots();
});

EDIT
Posted this comment below:
I should point out that Pots is actually a Backbonejs Collection with this declaration: var Pots = Backbone.Collection.extend({model: Pot});. The reason I did the event is because there IS a time when "Pots" isn't set (probably before the browser has loaded the file with Pots declared). The jsFiddle was just to simulate that time exists. In my actual code "otherTimer" doesn't exist and Pots IS eventually a Function but when I try to use it during the ObjectsAvailable event, it doesn't work.

Upvotes: 0

Views: 105

Answers (1)

Pointy
Pointy

Reputation: 413720

You never set the global variable "Pots" to any value, so it remains undefined.

The "ObjectsAvailable" handler looks like it attempts to set it, but

  1. It tries to call "Pots()" to do so, so that won't work, and
  2. It declares a local variable "Pots" too, so that hides the global one.

Another note: the fiddle is set up with the code to be run in the window "load" handler, so the "ready" handler is redundant.

Upvotes: 3

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