I am trying to create a JSON object in the particular format
{ "id": 12234 , "name": "Alex" , "gender": "Male"}
// My code starts here
var number = userid; // alert(userid) is 12345
var name= nameuser; // alert(nameuser) is Alex
var g= gender; // alert(gender) is male
var userObj = { "id": number , "name": name , "gender":g}
I tried `JSON.stringify(userObj); ,
that returns the object type as
{"id":"12345" , "name":"Alex" , "gender":"Male"}
but this is not what I want as I want the number to be 12345 and not "12345".
also tried stringifying the fields inside the object like
{ "id": number , "name":JSON.stringify(name) ,gender: JSON.stringify(g)}
but when I do alert(userObj) my object type is Object object and this is not a format the server recognises.
I am sure there is a workaround for this but I am unable to figure one out
JSON works with strings exclusively. It's invalid to have anything other than a string, array, or other JSON object in JSON. That said, a "number" is not allowed; it needs to be a string. Whatever you are working with with the JSON later needs to be able to change the string back it to a number, if necessary. JavaScript usually does a good job of coercing these.
On the server side you can just do something like
obj = json_decode(source)
obj.id = (int)obj.id
I think that your solution will come down to what you want to DO with the JSON, rather than how you want it to be formatted.
If you're using it in other JavaScript code, then the JSON.parse method is going to take care of most of your issue on the other side (with automatic type-casting dealing with the rest).
If you're using it on the server-side, again, PHP or similar will decode the object appropriately.
And if it's a more-strict language on your server, all you need to do is remember which parameters need to be cast to boolean or to int/float.
The below code from your question is valid JSON.
{ "id": 12234 , "name": "Alex" , "gender": "Male"}
I am guessing that the problem you have is that your userid variable is a string, not a number. If so, try
var number = parseInt(userid, 10);
(The 10 parameter indicates that you are using base 10 numbers as opposed to something like binary or hex).
store the object type as one of the property and use it to convert the way you want.
Related
I am using JSON to carry information from NodeJS (server side) to my client side. When I try to parse the JSON in the client side, it outputs only the last element, in this case, 'name: "Sam"'. I want all the elements to be outputted.
I have tried using an array and a variable to be assigned the parsed data. I have also directly tried logging it to the console with: [console.log(JSON.parse(this.response));]. All three gave the same result.
The first console.log returns all the elements in JSON form. The second one returns only the last one. There are 3 elements in total.
I expect all the elements to be assigned to the variable.
request.open('GET', 'http://localhost:3000/listofvoted', true);
request.onload = function () {
console.log(this.response)
console.log(JSON.parse(this.response));
}
request.send();
The JSON I receive:
{
"name": "Bran",
"name": "Ram",
"name": "Sam"
}
Although JSON (which is just a notation) allows for duplicate key names, the guidance is that that they SHOULD be unique. If you want to use JSON to create a JavaScript Object, then you are constrained by the fact that a JavaScript Object cannot have duplicate keys. So although you have valid JSON, it cannot be represented by a JavaScript Object and therefore it will not survive a round trip of being parsed (JSON converted to a JavaScript Object) by JSON.parse and then converted back to JSON.
For your own convenience of working in JavaScript, you could consider changing the JSON representation of your information so that it can be represented as a JavaScript Object.
Here are some alternative ways of representing what you have that may work:
Use an array of discrete objects:
[
{ "name": "Bran" },
{ "name": "Ram" },
{ "name": "Sam }"
]
Use an array of names:
{
"names": [ "Bran", "Ram", "Sam" ]
}
As a final, heavy-handed approach, you don't have to convert your JSON to a JavaScript object. You can parse it using a parser that allows you to provide your own handlers for the syntactic elements that occur in the JSON string and you can handle the duplicate keys in whatever way you wish. May I suggest the clarinet library for doing so.
See also, How to get the JSON with duplicate keys completely in javascript
I have some code that returns something like this:
body: '[
{
name: "name",
lastname: "lastname"
},
{
name: "name",
lastname: "lastname"
},
{
name: "name",
lastname: "lastname"
}
]'
Of course extracting the body is a simple object.body however, to get rid of the '' that wraps the array is just destroying me. I tried doing object.body.slice(1,-1) to get rid of them, it didnt work. I'm clearly not using the object properly.
How can I "extract" the array from within the body into a usable array?
It sounds like you want to evaluate the content of the string. Assuming whatever code building this string can't actually build JS objects to begin with, you can use eval or Function to generate the objects you need.
var data = eval(string);
Note that you must be sure that the source of the string is safe and reliable, otherwise you could be evaluating malicious code. There may also be performance consequences to using eval.
Using Function is a tiny bit safer, only because the code can not access your local variables. It should also avoid the performance costs of eval.
var data = Function("return (" + string + ");")();
Same warning about malicious code though.
If the string data was valid JSON, you could use JSON.parse, but it isn't, so you can't. To avoid security issues, either have the source provide valid JSON data, or write your own minimal parser to parse the data.
With a valid JSON string, you could just parse the string for an object with JSON.parse, if you have .
array = JSON.parse(string);
You can use split function and then take the first element, let me say
var a = '[{name: "name",lastname: "lastname"},{name: "name",lastname: "lastname"},{name: "name",lastname: "lastname"}]';
var s = a.split("'");
s[0] will return you the desired result
This may be a very simple question but I really can't seem to make it work.
I have several JSON lines and a notes array.
Using notes.push(JSONline) I am saving one JSON line per array position, I assume, so in the following manner:
//notes[1]
{"id":"26","valuee":"20","datee":"2016-04-05T15:15:45.184+0100","id2":51}
//notes[2]
{"id":"27","valuee":"134","datee":"2016-04-05T15:15:47.238+0100","id2":53}
//notes[3]
{"id":"26","valuee":"20","datee":"2016-04-05T15:15:45.184+0100","id2":52}
Here is my problem: I want to print one specific attribute, for example id from one specific JSON line in the array. How can I do this?
When I do console.log(notes) it prints all the JSON lines just as expected. But if I do console.log(notes[1]) it prints the first character of the JSON line in that position, not the whole line.
Similarly console.log(notes[1].id) does not print the id from the first JSON line, in fact it prints 'undefined'.
What am I doing wrong?
Thank you so much.
I'd recommend that you parse all the json when you are pushing to notes, like:
notes.push(JSON.parse(JSONLine))
If you are somehow attached to having json strings in an array instead of objects, which I wouldn't recommend, you could always just parse once you have the jsonLine id
JSON.parse(notes[id]).id
Basically, you want to use JSON.parse for either solution and I'd strongly recommend converting them to objects once at the beginning.
You need to remember that JSON is the string representation of a JS object. JS strings have similar index accessor methods to arrays which is why you can write console.log(notes[0]) and get back the first letter.
JavaScript doesn't allow you to access the string using object notation, however, so console.log(notes[0].id) will not work and the reason you get undefined.
To access the data in the string using this method you need to parse the string to an object first.
var notes = ['{"id":"26","valuee":"20","datee":"2016-04-05T15:15:45.184+0100","id2":51}'];
var note0 = JSON.parse(notes[0]);
var id = note0.id;
DEMO
This leaves the question of why you have an array of JSON strings. While it's not weird or unusual, it might not be the most optimum solution. Instead you could build an array of objects and then stringify the whole data structure to keep it manageable.
var obj0 = {
"id": "26",
"valuee": "20",
"datee": "2016-04-05T15:15:45.184+0100",
id2: 51
};
var obj1 = {
"id": "27",
"valuee": "134",
"datee": "2016-04-05T15:15:47.238+0100",
"id2": 53
}
var arr = [obj0, obj1];
var json = JSON.stringify(arr);
OUTPUT
[
{
"id": "26",
"valuee": "20",
"datee": "2016-04-05T15:15:45.184+0100",
"id2": 51
},
{
"id": "27",
"valuee": "134",
"datee": "2016-04-05T15:15:47.238+0100",
"id2": 53
}
]
You can then parse the JSON back to an array and access it like before:
var notes = JSON.parse(json);
notes[0].id // 26
That's because you have {"id": "value"... as a string in your key value pairs. "id" is a string so you can't reference it like a property. 1. use
var notes = JSON.parse(notes);
as mentioned in the comments by The alpha
or remove the quotes try
{id:"26", ...}
that's why notes[i].id is returning undefined
I have the following standard Javascript assignment statement returned as the output form a webservice call. I need to get the JSON array object out of it and was wondering if I can somehow use NSRegularExpression to do that.
I have no control over the web service so it has to continue returning a Javacript assignment stmt as in the attached snippet below.
Can anyone suggest an objective-c code snippet that accomplishes this task? I could receive sub-array and sub hashes as part of the individual elements as well...
var collection = [
{
"id": "4444",
"name" : "Bill Smith",
"position" : "tester"
},
{
"id": "4444",
"name" : "Bill Smith",
"position" : "tester"
}
];
You can write something like this:
NSArray *myJSONArray = #[
#{
#"id": #"4444",
#"name" : #"Bill Smith",
#"position" : #"tester"
},
#{
#"id": #"4444",
#"name" : #"Bill Smith",
#"position" : #"tester"
}];
You can use NSJSONSerialization to take an NSData with your JSON, and parse it into a native Foundation object.
In this case, if you receive the NSData from the JSON snippet you pasted, you'd have an NSArray returned which contains 2 NSDictionary objects. Here is how you can accomplish that using NSJSONSerialization:
[NSJSONSerialization JSONObjectWithData:myData options:NSJSONReadingMutableLeaves error:&error];
Note that the documentation says:
The data must be in one of the 5 supported encodings listed in the JSON specification: UTF-8, UTF-16LE, UTF-16BE, UTF-32LE, UTF-32BE. The data may or may not have a BOM. The most efficient encoding to use for parsing is UTF-8, so if you have a choice in encoding the data passed to this method, use UTF-8.
So do ensure that you receive the data in one of those encoded formats. This is the quickest way to do it, it's built in to Cocoa and is very, very fast. Also, you can have different options than NSJSONReadingMutableLeaves.
Hope this helps :)
oh well. I have not found any clever solution to this so I simply took a substring from the entire response object to extract all content between first and last {} or first and last []. Works just as well.
I am trying to figure out if I JSON.Stringify an object like this:
{"m_id":"xxx","record":
{"USER":"yyy","PWD","zzz","_createdAt":
11111."_updatedAt":00000},"state":"valid"}
and then try to JSON.Parse out only the USER and PWD, not have to just call the object, but go through stringify. how would that work?
thanks.
I'm not sure why you're talking about stringifying your object. You'd stringify it if you needed to send the data across a network or something, not when you need to manipulate it in JS.
...how do I extract the strings in {...USER: "aaa", PWD: "zzz"...}?
Assuming you have a variable referring to the object, something like the following (with or without nice line breaks and indenting to make it readable, and with or without quotes around the property names):
var obj = {
"m_id": "xxx",
"record": {
"USER": "yyy",
"PWD" : "zzz",
"_createdAt": 11111,
"_updatedAt": 00000
},
"state": "valid"
};
Then you can access the properties in the nested record object as follows:
console.log( obj.record.USER ); // outputs "yyy"
console.log( obj.record.PWD ); // outputs "zzz"
// etc.
(Note: in your question you had two typos, a comma that should've been a colon in between "PWD" and "zzz", and a dot that should've been a comma in between 11111 and "_updatedAt". There's no way that JSON.stringify() would have produced the string that you showed with those mistakes.)
If you want the strings "USER", "PWD" etc as an array, then use Object.keys.
If you want to iterate them, just use a normal for-in enumeration.
I might have misunderstood the question, but if I think it is what it is then try using
var tmp = JSON.parse(string_to_convert)
this should suffice to convert your string to a proper Javascript Object
Then you can do
for(var index in tmp){
console.log(tmp[index]);
}
and this should list all the keys on the first set of properties. If you want to do a nested thing, then use recursion on the properties. Hope this makes sense...