Develop Reference

How to parse the following json string into an object?

var jsonString = '{"DeviceId":3,"results":{"1":"[{\"x\":513,\"y\":565,\"width\":175,\"hight\":208}]"}}';
var message = JSON.parse(jsonString);
I got an error saying Unexpected token u in JSON at position 0
at JSON.parse.
Could you please guide me what's wrong?
THanks in advance!

At the last few characters looks wrong. The :212 has no sense as the value (that long array) for key "1" was already set, so that later :212 looks weird
Also enclosing it in single quotes it makes that all be like a huge string, and not as an array structure.

See Results key as value contains a sub array which contain "1" key which as value contains a string enclosing another json array (but escaped as plain string, so no structurally accesible for the main object . But that string if post -processed the :212 is paired to what? , no key, no comma neighter , to the precedent whole array which already was the value, not the key?. Anyway weird.

In your JSON string, there is wrong something with ":212", as it's not valid JSON, because it doesn't have any property that it's mapping the value for. For example, you are mapping values for width and height with properties keys. But for "212", there is no property.
Here is the above JSON formatted:
var jsonString = '{"DeviceId":"3","results":{"1":"[{\\"x\\":513,\\"y\\":565,\\"width\\":175,\\"hight\\":208}]"}}'
var message = JSON.parse(jsonString);
If you want to format the results, you can do to it, there is no error on it:
JSON.parse(message.results['1'])
Here is the JS Bin link for above code: https://jsbin.com/fiyeyet/edit?js,console

Just an advice
Professional code is all about proper spacing, proper identation , proper commenting, don't try to write down all within one single line, structure it VISUALLY nice to see nice to read nice to comprehend, and you will be approved in most jobs.
Hint: declare a normal array/object , convert it to json string using the proper function, then use the string variable returned by the function to test your code or whatever doing. That way, you can write down in the source really nice the structure.

JSON parsing issue in javascript

I have below result returned from python script
{"a_paget_wilkes": "\/speaker\/a_paget_wilkes.json",
"aaron_clark": "\/speaker\/aaron_clark.json",
"aaron_dunlop": "\/speaker\/aaron_dunlop.json",
"aaron_ernst": "\/speaker\/aaron_ernst.json",
"aaron_hurst": "\/speaker\/aaron_hurst.json",
"abigail_miller": "\/speaker\/abigail_miller.json",
"abner_kauffman": "\/speaker\/abner_kauffman.json"}
So it is pretty well formatted JSON I believe. Javascript variable which has above data is called jsondata. Now in the chrome developer tool console when I try to access key valye pair by typing jsondata. I expect all keys to be listed as suggestion, but it shows me string properties like length, anchor, big, blink etc... instead
I tried even JSON.stringify first and then JSON.parse but still the same!!!
Any idea what is wrong in here?

jsondata is apparently a string containing your JSON, rather than a JavaScript object that would result from parsing your JSON.
To parse it, use JSON.parse.
I tried even JSON.stringify first and then JSON.parse but still the same!!!
JSON.stringify will take you in the wrong direction — it will wrap your entire string in a JSON string — and JSON.parse will only undo the JSON.stringify (recovering your original string), not parse your original string.
You need to call JSON.parse without calling JSON.stringify first.

Assign data from LocalStorage to a block of data (Angular2)

So, I used data declared by myself, but now i switch the code to LocalStorage, and I'd like to know, how to get the data from one element of LocalStorage, and insert it to a block of data from my program.
Here's a part of code which shows the procedure which i use for inserting data
let l = this.lists;
localStorage.setItem('lists', JSON.stringify(l));
l is of type string, and lists is an array with data block.
I wanted to use this command
this.lists = localStorage.getItem('lists');
but unfortunately,it wants a string element, and doesn't want to work with my lists element...
Info time:
LocalStorage is implementation of Storage interface and it accepts and
returns plain strings so every time you want to store there something
a little bit more complex you have to serialize when inserting
(JSON.stringify) and deserialize when retrieving (JSON.parse)

You can use JSON.parse()
The JSON.parse() method parses a JSON string, constructing the JavaScript value or object described by the string.
this.lists = JSON.parse(localStorage.getItem('lists'));
localStorage is implementation of Storage interface, It works on plain strings. When you want to work with complex object serialize it using JSON.stringify() and deserialize using JSON.parse()

Simple JSON stays undefined

I have an AJAX call that get's a simple JSON back on success, writing the returned JSON into the variable named data.
The returned JSON has been generated within PHP through:
echo json_encode(array('message'=>0);.
Back in my javascript console I'm logging the output of data with console.log(data);. The output is {"message":0}, which seems correct.
However, if I try to log console.log(data.message); I am getting message: undefined.
What am I doing wrong in accessing this pretty basic JSON object?
I've been reading some articles about how to move through JSON object, e.g. https://www.tutorialspoint.com/json/json_overview.htm but I can't find my mistake.
Hopefully you can point me into the right direction :)
Thank you :)

You have to do JSON.parse(result) first to make it an object, because at the moment you're trying to access message property of a string.
You know there are 2 JSON functions in javascript, right...?
// returns string representation of the object
JSON.stringify(object);
// returns a new object built from the string
JSON.parse(object_stringified);

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.