Dereferencing a variable to its value to use in another function javascript

Question

function get_event_ids_from_dom()
{
    var event_ids = {};
    $.each(
    $("td.ms-cal-defaultbgcolor a"),
        function(index,value){
             var str = new String(value); 
             var id = str.substring(str.indexOf('=')+1,str.length);
             if(typeof(event_ids[id]) == "undefined")
             {
                event_ids[id] = this;
            }
            else
            {
                **event_ids.id.push(this);**

            }
        }
     )
        return event_ids;
}

In above javascript event_ids is a hashtable. I am trying to assign values to this hashtable.

A hashtable can be added with multiple values using "hashtable.key.push(value)". I am trying to do this using event_ids.id.push(this); in the above code.

I have declared "id" as a variable in the code. The problem is, I am not able to dereference variable "id" to its value.

Is this possible in jquery/javascript?

Example use of hashtable:

event_ids = {};
event_ids["1"]= 'John';
event_ids.1.push('Julie');

The above example would add john and julie to hash table.

@Ivaylo Slavov No it does not work. I am getting TypeError: event_ids[id].push is not a function, In firebug. Could you please check again? — zer0c00l
– zer0c00l, Commented Jun 23, 2011 at 14:19
Your example is not valid JavaScript: **event_ids.id.push(this);** ? And you shouldn't use the String class directly. It's just there to decorate string values with methods. When you call methods on a string value JavaScript is simply calling the methods on the prototype of String in the context of the string value. You're going to run into problems if you're using an object as a string instead of just a string. — Bjorn
– Bjorn, Commented Jun 23, 2011 at 14:24
@apphacker The value variable will have something like this "Business%20Development/Lists/Calendar/DispForm.aspx?ID=907". But it is in object form. I want to convert it into string to process it. Is it possible without using String class? — zer0c00l
– zer0c00l, Commented Jun 23, 2011 at 14:33
@apphacker got it from Ivaylo's answer. changed my code to value.toString() , Thanks for the info :-) — zer0c00l
– zer0c00l, Commented Jun 23, 2011 at 14:43

stackh34p · Accepted Answer · 2013-05-14 13:47:37Z

2

Try this instead:

function get_event_ids_from_dom() {
    var event_ids = {};
    $.each(
        $("td.ms-cal-defaultbgcolor a"),
        function(index,value){
            var str = value.toString(); 
            var id = str.substring((str.indexOf('=') + 1), str.length);
            if(typeof(event_ids[id]) == "undefined") {
                event_ids[id] = [];
            }
            event_ids[id].push(this);
        });
    return event_ids;
}

Please, note that while object["id"] is the same as object.id, object[id] is not.

edited May 14, 2013 at 13:47

answered Jun 23, 2011 at 14:18

stackh34p

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2 Comments

Bjorn Over a year ago

You should accept his answer if you like it. Also Ivaylo I can't vote up your answer until you get rid of that String use. :P

stackh34p Over a year ago

@apphacker, thanks for pointing out, it was a copy-paste error.

Bjorn · Accepted Answer · 2011-06-23 14:30:03Z

2

Nicola almost had it:

if(typeof(event_ids[id]) == "undefined") {
  event_ids[id] = [];
}
event_ids[id].push(this);

Also please read the comment I left for your question.

answered Jun 23, 2011 at 14:30

Bjorn

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1 Comment

Nicola Peluchetti Over a year ago

yes, stupid error i made. I corrected it. I think in his question he was trying to put bold around the line.

Nicola Peluchetti · Accepted Answer · 2011-06-23 14:31:12Z

1

In my opinion event_ids is an object (there are no hastables in javascript, just either indexed arrays or objects). What you are tring to do is using push (an array method) on something that is not an array so i think you must change something:

you could try:

         if(typeof(event_ids[id]) == "undefined")
         {
            event_ids[id] = [];// the property id of object event_ids is an array
            event_ids[id].push(this);
        }
        else
        {
            event_ids[id].push(this);

        }

It should work

edited Jun 23, 2011 at 14:31

answered Jun 23, 2011 at 14:14

Nicola Peluchetti

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3 Comments

Bjorn Over a year ago

event_ids[id][] = this; is not valid JavaScript.

Bjorn Over a year ago

The else statement is totally unnecessary.

Nicola Peluchetti Over a year ago

i didn't want to copy your answer! :) i just put correct code inside, it sure is unneccessary

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