Develop Reference

How to decode in JavaScript/Node.js a string of combined UTF16 and normal characters?

I have a huge JSON stringified into a string like this one:
"\\u007B\\u0022name\\u0022\\u003A\\u0022T\\u0065st\\u0022}"
I need to JSON.parse it to use as an object. Do you know any way to decode it?
I tried decodeURIComponent(), unescape(), different variants of .replace( /\\u/g, "\u" ) and I can not get it into the needed form.

You can convert UTF-16 to text using the following function:
function utf16ToText(s) {
return s.replace(/\\u[0-9a-fA-F]{4}/gi, match => {
return String.fromCharCode(parseInt(match.replace(/\\u/g, ""), 16));
});
}
Demo:
const r = utf16ToText("\\u007B\\u0022name\\u0022\\u003A\\u0022T\\u0065st\\u0022\\u007d");
console.log("As text: ", r);
const j = JSON.parse(r);
console.log("As JSON: ", j);
console.log("JSON Prop: ", j.name);
function utf16ToText(s) {
return s.replace(/\\u[0-9a-fA-F]{4}/gi, match => {
return String.fromCharCode(parseInt(match.replace(/\\u/g, ""), 16));
});
}

If your string is valid JSON, then you can use JSON.parse() to process the UTF16 for you. To make what you have valid JSON, you have to add double quotes to each end (inside the actual string) as all strings must be enclosed in double quotes in the JSON format. Here's an example:
let data = "\\u007B\\u0022name\\u0022\\u003A\\u0022T\\u0065st\\u0022\\u007d";
// to make this legal JSON so we can let the JSON parser parse it for us and
// handle the UTF16 for us, we need to put double quotes in the actual string at each end
// Then, it's legal JSON and we can parse it
let str = JSON.parse('"' + data + '"');
console.log(str);
console.log("type is", typeof str);
This gives you a result in string form:
{"name":"Test"}
This result is now legal JSON on its own. If you then wanted to parse that as JSON, could just call JSON.parse() on it again to turn it into an actual Javascript object:
let data = "\\u007B\\u0022name\\u0022\\u003A\\u0022T\\u0065st\\u0022\\u007d";
let str = JSON.parse('"' + data + '"'); // decoded string here
// now take the string and actually parse it into a Javascript object
let obj = JSON.parse(str);
console.log(obj); // Javascript object here
console.log("type is", typeof obj);
This gives you a resulting live Javascript object:
{name:"Test"}
The first call to JSON.parse() just takes your JSON string and decodes it into a Javascript string. Since that Javascript string is now also legal JSON for an object definition, you can call JSON.parse() on it again to turn it into a Javascript object.

Thank you for your input. Because of that, I got the solution:
let a = "\\u007B\\u0022name\\u0022\\u003A\\u0022T\\u0065st\\u0022}" original string
let b = '"' + a + '"' adding " in order to make a valid stringified JSON
let c = JSON.parse(b) that will produce a partially decoded string (partially because some of the \uXXXX characters can stay in the string)
let solution = JSON.parse(c) that will create an object with all the characters decoded
Big thanks to #jfriend00

How to remove special character from Json without parsing

I want to remove some special character from json without parsing
the json into object.
Parsing would result into error that is why i wanted to do without json.parse().
below is my json:
{
"id":324,
"name":"first",
"body":{
"sbody": "<p>\\\The New Stroy\\\</p>"
}
}
desired output:
{
"id":324,
"name":"first",
"body":{
"sbody": "<p> The New Stroy </p>"
}
}

Looks like your input is a string and the error you are getting is when using JSON.parse.
Try this
var response = '{"sbody": "<p>\\\The New Stroy\\\</p>"}';
response = response.replace(/\\/g, "");
var obj = JSON.parse(response);
console.log(obj);

You need to run .replace on your string:
var string = '{"id":324,"name":"first","body":{"sbody":"<p>\\\The New Stroy\\\</p>"}}';
string = string.replace(/\\/g,'');
console.log(string);
//{"id":324,"name":"first","body":{"sbody":"<p>The New Stroy</p>"}}
The reason the pattern is /\\/ is because \ is used to escape characters. With a single \ we end up escaping the /. What we need to do here is escape the escape character to turn it into a literal string character: \\.
The g after the pattern means to search for the pattern "globally" in the string, so we replace all instances of it.

var obj = {
"id":324,
"name":"first",
"body":{
"sbody": "<p>\\\The New Stroy\\\</p>"
}
}
// Convert object to string
var str = JSON.stringify(obj);
// Remove \ from the string
var convertedStr= str.replace(/\\/g,'');
// Convert updated string back to object
var newObj = JSON.parse(convertedStr);

How should a JSON string with quotes inside can be parsed with javascript

var str = '{"Language":"en","Type":"General","Text":""Mela" means "apple" in Italian"}';
Now JSON.parse(str) throws this error
Uncaught SyntaxError: Unexpected token M in JSON at position 43
Now replacing quotes escapes whole string and parsed JSON is not usable anymore
str = str.replace(/\\([\s\S])|(")/g,"\\$1$2");
"{\"Language\":\"en\",\"Type\":\"General\",\"Text\":\"\"Mela\" means \"apple\" in Italian\"}"
Other solutions like below do not seem to be working in this scenario
How to escape a JSON string containing newline characters using JavaScript?

You need to add a backslash before each double quote within your string as:
const str = '{"Language":"en","Type":"General","Text": "\\"Mela\\" means \\"apple\\" in Italian"}';
const obj = JSON.parse(str)
console.log(obj.Text)

In JSON you don't escape double quotes of the property name or the begging of the property value, just escape what's inside property value:
{\"Text\":\"\"Mela\" means ....
It should be like this:
{"Text":"\"Mela\" means ....

This can be done with multiple replacements:
var str = '{"Language":"en","Type":"General","Text":""Mela" means "apple" in Italian"}';
str = str.replace(/"/,"'"); //Replace all " with '
str = str.replace(/{'/,'{"') //Restore " to start of JSON
str = str.replace(/','/,'","'); //Restore " around JSON , separators
str = str.replace(/':'/,'":"'); //Restore " around JSON : separators
str = str.replace(/'}/,'"}'); //Restore " to end of JSON
str = str.replace(/'/,'\"'); //All remaining ' must be inside of data, so replace with properly escaped \"
console.log(str);
EDIT: A problem with this solution is that is will also replace original ' characters with " inside the text.

JSON.parse() returns a string instead of object

I'd hate to open a new question even though many questions have been opened on this same topic, but I'm literally at my ends as to why this isn't working.
I am attempting to create a JSON object with the following code:
var p = JSON.stringify(decodeJSON('{{post.as_json}}'))
var post = JSON.parse(p);
console.log(post); // Debug log to test if code is valid
And the decodeJSON function:
function decodeJSON(json) {
var txt = document.createElement("textarea");
txt.innerHTML = json;
return txt.value.replace(/u'/g, "'");
}
console.log(post) returns the following JSON string:
{'content': 'kj fasf', 'uid': '4eL1BQ__', 'created': '07/09/2017', 'replies': [], 'tags': ['python'], 'by': {'username': 'Dorian', 'img_url': '/static/imgs/user_Dorian/beaut.jpg'}, 'likes': 0}
After scanning through the string I am pretty sure that the JSON is valid and there are no syntax errors. However, when running JSON.parse(p) Instead of receiving an object, I get a string back. What could be the cause?

That's because decodeJSON returns a string, and JSON.stringify turns that string in another string.
In the other hand, you used JSON.strigify() method on a string. You should stringify an object, not string.
JSON.stringify() turns a javascript object to json text and stores it
in a string.
When you use JSON.parse you obtain the string returned by decodedJSON function, not object.
Solution:
var p = JSON.stringify('{{post.as_json}}');
var post = JSON.parse(p);
console.log(post);
It gives me Uncaught SyntaxError: Unexpected token ' in JSON at
position 1
The solution is to modify your decodeJSON method.
function decodeJSON(json) {
var txt = document.createElement("textarea");
txt.innerHTML = json;
return txt.value.replace(/u'/g, '\"');
}
var p = decodeJSON('{{post.as_json}}');
var post = JSON.parse(p);
console.log(post);

The issue in your code is that you are performing JSON.stringify on a string itself. So on parsing the result of this string will be a string. In effect, you have stringified twice and parsed once. If you parse it once more you will get a JSON. But for solution avoid the stringification twice.
Replace in your code.
var p = decodeJSON('{{post.as_json}}');
That will work

Split object in Node.js

Yesterday i solve my problem spliting my string with "\" but today i have the same problem but with a object...
2|wscontro | [2017-05-31 15:57:23.145] - debug: /opt/wscontroller/wscontroller-api/routes/ubus UbusController 63320169-611e-43f5-880e-9b1a13152cfd getDeviceServicesById signature {"config":"wireless","section":"radio0","values":"{\"disabled\":0}"}
2|wscontro | [2017-05-31 15:57:23.145] - debug: /opt/wscontroller/wscontroller-api/routes/ubus UbusController 63320169-611e-43f5-880e-9b1a13152cfd getDeviceServicesById signature "object"
I need to have only signature =>
{"config":"wireless","section":"radio0","values":{"disabled":0"}}
Can anyone help me? I try to convert to String this object and split doing
var aux = signature.split('\\').join('');
var jsonObject = JSON.parse(aux);
But i get the same result {"config":"wireless","section":"radio0","values":"{\"disabled\":0"}}
My last post: Split string by "\" Node.js
anyone can help?

is this you wanted?
var str =' {"config":"wireless","section":"radio0","values":"{\"disabled\":0"}';
console.log(str.replace(/\\/g,''));

Your object should be like you said in your last comment {"config":"wireless","section":"radio0","values":"{\"disable‌​d\":0}"} then:
var jsonstring = "{"config":"wireless","section":"radio0","values":"{\"disable‌​d\":0}"}";
var escapedJsonstring = jsonstring.split('\\').join('');
var json = JSON.parse(escapedJsonstring);
json.parsedValues = JSON.parse(json.values);
console.log(json);
Finally you have parsed object in json variable. The main idea is that the values attribute has also string value and not object value. So you need to parse it again as JSON. Result of this parsing is stored in json.parsedValues, but you can rewrite the values string with object using this: json.values = JSON.parse(json.values);