Develop Reference

How To Parse A String Of Concatenated JSON In Browser?

I'm using Socket.IO to move data to the browser. The data sent is a stream of JSON objects, and when it arrives at the browser, it becomes one large string of JSON. The problem is, this JSON can't be parsed by JSON.parse() because it's not "real" JSON.
The data structure can be arbitrary so a RegEx might not do the trick. And this current setup is only temporary. Eventually this stream of JSON will be pre-processed server-side so a stream will not need to be sent to the browser, so I'd like to keep the AJAX/Socket.IO setup I have right now instead of switching over to a JSON stream parser like OboeJS.
What can I do to parse this string of concatenated JSON?
For clarity, the JSON will look like this:
{"a":"A"}{"b":"B"}{"c":"C"}
And I'm trying to parse it in such a way that I can access them like:
console.log(Object.a) //A
console.log(Object.b) //B
console.log(Object.c) //C

In your particular case, you could use Array.prototype.reduce to merge all JSON objects into one:
var unstructuredJson = '{"a":"A"}{"b":"B"}{"c":"C"}';
var jsonArray = "[" + unstructuredJson.split("}{").join("},{") + "]";
var objectArray = JSON.parse(jsonArray);
var result = objectArray.reduce(function(result, item) {
Object.keys(item).forEach(function(propertyName) {
result[propertyName] = item[propertyName];
});
return result;
}, {});
document.body.textContent = JSON.stringify(result);
OP said in some comment:
[...] Each JSON might have nested data like {{}{}}{}{}{}
Then, above approach is broken on this case.
My two cents is that you should put some separator character when you stream these JSON objects and life will be easier: you'll be able to split parent objects easily and you'll just need to change split("}{") with the whole separator.
I suggest you that you use some character that will never happen as part of any property value. You can find a control character on this Wikipedia article: Control character

If each substring is valid JSON but the concatenated part isn't, you can turn the string into a valid array literal and use JSON.parse, then you can process each object using Array methods, e.g. forEach:
var s = '{"a":"A"}{"b":"B"}{"c":"C"}';
var obj = JSON.parse('[' + s.replace(/}{/g,'},{') + ']').forEach(function (obj) {
document.write(JSON.stringify(obj) + '<br>');
});
Or if you want it as a single object:
var s = '{"a":"A"}{"b":"B"}{"c":"C"}';
var obj = JSON.parse(s.replace(/}{/g,','));
document.write(JSON.stringify(obj));

You can use JsonParser to parse concatenated json objects:
ObjectMapper mapper = new ObjectMapper();
JsonFactory factory = new JsonFactory(mapper);
JsonParser parser = factory.createParser(YourJsonString);
List<YourObject> YourObjectList = new ArrayList<>();
Iterator<YourObject> iterator = parser.readValuesAs(YourObject.class);
while(iterator.hasNext()) {
YourObject yourObject = iterator.next();
loginSignalsList.add(yourObject);
}

Split the large string {a:'A'}{b:'B'}{c:'C'} and parse them individually

convert string to dynamic array with variables in javascript

How would I take a string (that I got from a page using jQuery's text()) such as:
var myData = "[{name:'xxx',data:[1,2,3,4,5]},{name:'yyy',data:[5,4,3,2,1]}]"; //this is a string :(
And turn it into the actual javascript object that I need, so for example:
var myObject = [{name:'xxx',data:[1,2,3,4,5]},{name:'yyy',data:[5,4,3,2,1]}];
So 'name' and 'data' will be non-dynamic variables, however names value, the data array and the length of myObject will be dynamic.
Not really sure where to start with this one. I am guessing that I will have to do a whole lot of spliting and looping, but I am open to suggestions.

Well, it can be done very easily:
var myObject = eval(myData);
However, you should be aware of the risks of the eval function. As it runs the value as a Javascript expression, it would also run any harmful code that would be in the string, so you should only use it when you have full control over what's in the string.
If you could change the format to be JSON, you could safely parse it without risks of code injection:
var myData = '[{"name":"xxx","data":[1,2,3,4,5]},{"name":"yyy","data":[5,4,3,2,1]}]';
var myObject = $.parseJSON(myData);

You mean,
var myObject = eval('(' + myData + ')');
?
EDIT
Its major con is that you can put any javascript code (not only JSON) to eval (Chrome's F12 lets anyone to exploit this). AS you are using jQuery, best choice will be
var myObject = $.parseJSON(myData);
for cross browser compatibility.
$.parseJSON
Takes a well-formed JSON string and returns the resulting JavaScript
object. Passing in a malformed JSON string may result in an exception
being thrown. For example, the following are all malformed JSON
strings:
{test: 1} (test does not have double quotes around it).
{'test': 1} ('test' is using single quotes instead of double quotes).

Javascript: How to convert JSON dot string into object reference

I have a string: items[0].name that I want to apply to a JSON object: {"items":[{"name":"test"}]} which is contained in the variable test. I want to apply that string to the object in order to search it (test.items[0].name). I can only think of one way to do this: parse the square brackets and dots using my own function. Is there another way I can do this? Perhaps using eval? (Even though I'd LOVE to avoid that...)
For clarity:
I have a JSON object, what is inside of it is really irrelevant. I need to be able to query the object like so: theobject.items[0], this is normal behaviour of a JSON object obviously. The issue is, that query string (ie. items[0]) is unknown - call it user input if you like - it is literally a string (var thisIsAString = "items[0]"). So, I need a way to append that query string to theobject in order for it to return the value at theobject.items[0]

function locate(obj, path) {
path = path.split('.');
var arrayPattern = /(.+)\[(\d+)\]/;
for (var i = 0; i < path.length; i++) {
var match = arrayPattern.exec(path[i]);
if (match) {
obj = obj[match[1]][parseInt(match[2])];
} else {
obj = obj[path[i]];
}
}
return obj;
}
var name = locate(test, 'items[0].name');

...JSON doesn't have objects, it's just a string.
If you're dealing with an object (ie: you can reference it using dot/bracket notation) then it's just a JavaScript object/array...
So depending on what the deal is, if you're dealing with a 100% string:
'{"name":"string","array":[0,1,2]}'
Then you need to send it through JSON.parse;
var json_string = '{"name":"string","array":[0,1,2]}',
js_obj = JSON.parse(json_string);
js_obj.name; // "string"
js_obj.array; // [0,1,2]
js_obj.array[1]; // 1
If it's not a string, and is indeed an object/array, with other objects/arrays inside, then you just need to go:
myObj.items[0].name = items[0].name;
If it IS a string, then .parse it, and use the parsed object to do exactly what I just did.
If it needs to be a string again, to send to the server, then use JSON.stringify like:
var json_string = JSON.stringify(js_obj);
Now you've got your modified JSON string back.
If you need to support GhettoIE (IE < 8), then download json2.js from Douglas Crockford, and add that script on the page conditionally, if you can't find window.JSON.

Iterate JSON object string

I am a javascript noob. I have a JSON string created by google gson API after creating the json string which I am passing it to my javascript function. So in a javascript variable I have a string as follows
'{"validationCode":"V10291","caseNumber":"2010CF101011","documentSource":"EFILE","countyDocumentID":"CD102","documentTitle":"D Title","signedDate":"01/01/2012","signedBy":"CPSJC","comments":"YES Comments"}'
How to iterate over this or get a value of the key something like I have to find validationCode or caseNumber, but this is String? Any suggestions are welcome

You can get it into a native JavaScript object with JSON.parse:
var obj = JSON.parse(yourJSONString);
Then you can iterate the keys with a standard for in loop
for(var k in obj)
if ({}.hasOwnProperty.call(obj, k))
console.log(k, " = ", obj[k]);
Or access particular keys like validationCode or caseNumber directly:
var caseNum = obj.caseNumber;
var validationCode = obj.validationCode;
Note that really old browsers don't support JSON.parse, so if you want to support them, you can either use Papa Crockford's json2, or jQuery, which has a parseJSON utility method.

You could do a for ... in to loop through the object properties:
var person={fname:"John",lname:"Doe",age:25};
var x;
for (x in person)
{
document.write(person[x] + " ");
}
http://www.w3schools.com/js/js_loop_for_in.asp

If you are using JQuery framework you can use : jQuery.parseJSON
If not you can use JSON.parse() or you can use eval (which is less safe).

Problem parsing JSON

I encounter problems tring to consume a third party web servive in JSON format. The JSON response from the server kinda looks like this:
{
"ID":10079,
"DateTime":new Date(1288384200000),
"TimeZoneID":"W. Europe Standard Time",
"groupID":284,
"groupOrderID":10
}
I use JavaScript with no additional libs to parse the JSON.
//Parse JSON string to JS Object
var messageAsJSObj = JSON.parse(fullResultJSON);
The parsing fails. A JSON validatior tells me, "new Date(1288384200000)" is not valid.
Is there a library which could help me parse the JSON string?

Like others have pointed out, it's invalid JSON. One solution is to use eval() instead of JSON.parse() but that leaves you with a potential security issue instead.
A better approach might be to search for and replace these offending issues, turning the data into valid JSON:
fullResultJSON = fullResultJSON.replace(/new Date\((\d+)\)/g, '$1');
You can even go one step further and "revive" these fields into JavaScript Date objects using the second argument for JSON.parse():
var messageAsJSObj = JSON.parse(fullResultJSON, function (key, value) {
if (key == "DateTime")
return new Date(value);
return value;
});
Here's an example: http://jsfiddle.net/AndyE/vcXnE/

Your example is not valid JSON, since JSON is a data exchange technology. You can turn your example into a Javascript object using eval:
var almostJSON = "{
"ID":10079,
"DateTime":new Date(1288384200000),
"TimeZoneID":"W. Europe Standard Time",
"groupID":284,
"groupOrderID":10,
}";
and then evaling it:
var myObject = eval('(' + almostJSON + ')');
Then, myObject should hold what you're looking for.
Note that functions are not allowed in JSON because that could compromise security.

try var obj = eval('(' + fullResultJSON + ')'); and you'll have the object like Pekka said. Don't forget to use the extra '()' though. And indeed json should have both property and value enclosed in quotes.

Parsing fails because all you can parse in a json object are null, strings, numbers, objects, arrays and boolean values so new Date(1288384200000), cannot be parsed
You have also another problem, last property shouldn't have the trailing comma.