Develop Reference

JSON.stringfy return data different compared with the object

I have some code:
console.log("444444: ", profile, JSON.stringify(profile))
when I check the log:
Basically I want to know why I can not see
value: [0]
and i want to pass this profile object to backend and looks like backend is not getting this value field.

Probably, you remove profile.value somewhere after you outputted it to console.log(). Try looking for delete profile.value; or profile.value = undefined;.

Try to parse the data first and then stringify
JSON.parse(JSON.stringify(profile))

Meteor: retrieve value from document in collection

I have a Collection named "balance". I want to get the value of one document in the collection. In order to get only the latest element in the collection I use this query:
db.balance.find().sort({date: -1}).limit(1);
There's a column called 'value' and I want to get that.
db.balance.find().sort({date: -1}).limit(1).value; however does not show the data I want. It shows nothing:
What's wrong with it?

find returns a cursor. You'll need to convert it to an array in order to actually extract the value. Try this:
db.balance.find().sort({date: -1}).limit(1).toArray()[0].value;
This is, of course, much easier inside of meteor (either in code or via meteor shell) because you can do:
Balance.findOne({}, {sort: {date: -1}}).value;

Acessing Object Elements

When I do
console.log(JSON.stringify(chunks1[1].data)))
This is the log:
"{\"data\":{\"0\":0.00006103515625,\"1\":0.00018310546875,\"2\":0.00018310546875,\"3\":0.0001220703125,\"4\":-0.0003662109375,\"5\":-0.000396728515625,\"6\":-0.000518798828125,\"7\":-0.00054931640625,\"8\":-0.00048828125,...
Now can I access the elements of "data"?
If I do
chunks1[1].data[0]
I get nothing. And
chunks1[1].data.1
Obviously I will get an error.

data is an object. Apart from getting the property with data.propertyName, you can also get it using an array notation, specifying the property name as a string. Like this:
chunks1[1].data['0']
#aduch makes a good point there. There is another 'data' in the output which I overlooked. The object with the numeric properties is actually a subobject, so the correct notation would be:
chunks1[1].data.data['0']

Currently, you are trying to access the elements of data as if it were an array, with numbered indexes, e.g. chunks1[1].data[0].
Instead, because data is an object, you should be using a string index: chunks1[1].data["0"].
And, because in your console.log example, chunks1[1].data is an object containing data as a key, your final accessing scheme should look like:
chunks1[1].data.data["0"]

Setting Object to Chrome Storage

So I'm trying to save an object via the chrome.storage API. The relevant code is:
var images = null;
var storage = chrome.storage.sync;
var key = "key";
images = getImages(source);
alert(images.length); // returns 4
storage.set({key: images});
storage.get("key", function(result) {
alert(result.length); // returns undefined
});
I'm tested that immediately after the getImages() function, images is a wrapped set JQuery object with a length of 4. However, when I try to access images.length via the storage.get callback, the result is undefined.
Could someone help identify the error in how I am storing and/or retrieving this JQuery object?
Update 1:
Thank you all for your help. As clarification for the use case, I am using chrome.storage instead of localStorage because I plan to pass extension info to another script.
Fortunately, TranQ/Xan's solution has enabled me to access the array via the storage.get call.
I'm still experiencing issues working with the wrapped set JQuery object stored in the array but I'll post a separate question since the current solution encapsulates broader use cases.

TranQ's comment is on point.
Presumably, images is an array. You store that array under the "key" key.
When you execute the get() function, it returns an object populated with all key-value pairs you asked, even if you only ask for one key.
So, result is an object {key : [/* something */]}. Objects do not have a length property, and you get undefined
You need to use result.key (or result["key"]) to access your array.

append object to innerHTML and get that object from innerHTML

here is an example in jsfiddle.
I want to know if I can append a javascript object to innerHTML, that get that object again from innerHTML as object.
something like,
alert((this.innerHTML).html);
that's just an example, don't ask me why do you need this?
I'm trying to edit an existing code, and I have to do this so.
I have to transfer an object via div.innerHTML.

Check this jsfiddle. In it, I add the object to the div as a 'data-'-attribute, using JSON to convert it to a string. After that, adding some comment to the div triggers the DOMSubtreeModified-handler, in which the 'html'-part of the object is retrieved and alerted. It that something to work with?

In this case, quite possible your only option is to convert your object to string and then put that into the element. (This is done by looping through the key, values building the string as you go.)
You would reverse the process to convert it back into an obj.
I know some javascript libary's have helper functions to make this process very simple.
You could try adding the data directly onto the dom element, rather than as its content..
tempDiv.objData = myObject;

It was suggested to use JSON, but no code. So:
function addObjAsJSON(el, obj) {
el.setAttribute('data-myJSON', encodeURIComponent(JSON.stringify(obj)));
}
function getObjAsJSON(el) {
return JSON.parse(decodeURIComponent(el.getAttribute('data-myJSON')));
}
That should allow you to add anything as a serialised object, then get it back. You should add some error checking to make it robust though (e.g. check that you get a string back from the call to getAttribute).
For user agents that don't have built-in JSON support, see json.org which has a link in the javascript section to json.js.