Unable to access the data JSON, using variables

Question

I tried to get information about the status of some of the buttons in JSON using the $. getJson () ID with a dash is broken into two parts, and they entered into an array regarr. But I can not get data from JSON in this query:

data.regarr[0].regarr [1] //regarr is undefined

HTML:

<div class='buttons' id='lamps-fire1'>OFF</div>

My JSON:

{"lamps":{"fire1":"off","fire2":"off","fire3":"off"},"motor":"on","temperature":"12"}

JavaScript

$(document).ready(function()
{
    function reloadvalues()
    {
        $('.buttons').each(function ()
        {
                var id=$(this).attr('id');
                var re=/-/;
                var re2=/[a-z0-9]{1,}[^-][a-z0-9]{1,}/ig;
                var regarr=[];
                 regarr=id.match(re2);
                if (id.search(re)==-1)
                {
                    $.getJSON('homeapi.ini','tire=none&id='+encodeURIComponent(id),function (data)
                    {
                    if (data.motor=='off')
                    {
                        $(this).html('OFF.');
                    }
                    else{
                        $(this).html('ON.');
                    }
                    });
                }
                else{
                    $.getJSON('homeapi.ini','',function (data)
                    {
                    if ((regarr[1]!='undefined')||(regarr[0]!='undefined')||(regarr !='undefined'))
                    {
                    if (data.regarr[0].regarr[1]=='off')
                    {
                        $(this).html('OFF.');
                    }
                    else{
                        $(this).html('ON.');
                    }
                    }
                });
                }
            });
    }
    setInterval(function (){
        reloadvalues();
        },5000);
});

Maybe someone knows what went wrong?

wait there's not key regarr in your data JSON is there? you probably want domething like data[regarr[0]][regarr[1]]... — Carlo Moretti
– Carlo Moretti, Commented Aug 7, 2012 at 11:02

nbrooks · Accepted Answer · 2012-08-07 11:10:46Z

1

The reference this is not the same within the callback function scope as it is within the each loop. You will have to cache a reference to it before entering the sub-functions. Then, within your callback function blocks in your $.getJSON method, use the stored reference (in this case I called it self) instead of this:

$(document).ready(function() {
    function reloadvalues() {
        $('.buttons').each(function() {
            var self = this;

            /* ... */ 
            if (id.search(re) == -1) {
                $.getJSON('homeapi.ini', 'tire=none&id=' + encodeURIComponent(id), 
                function(data) {

                    if (data.motor == 'off') {
                        $(self).html('OFF.');
                    }
                    else {
                        $(self).html('ON.');
                    }
                });
            }
            /* ... */
        });
    }
});

Regarding the reference error, when using property names stored in variables, you have to de-reference the json object using [ ] rather than a simple .. In this case:

Replace ~~data.regarr[0].regarr[1]~~ with data[regarr[0]][regarr[1]]

edited Aug 7, 2012 at 11:10

answered Aug 7, 2012 at 11:02

nbrooks

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2 Comments

Zamony Over a year ago

Hello.But now in Firebug:TypeError: data.regarr is undefined if (data.regarr[0].regarr[1]=='off'). Nothing has changed:(

Zamony Over a year ago

No errors! But I have a problem. When I change the JSON data to the server, the changes do not appear on the page. Most likely I'm doing something wrong. Here is my code: pastebin.com/AyT2b8hy

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