extract array from string that is a valid JSON

Question

var myvar = '
    myname({    "country":{        "cities":[ {"id":"3", "population":"3700"},{"id":"5", "population":"3730"}]   } });';

So that myvar is a string.

How to get citiesArr array of city objects from myvar?

Refer http://stackoverflow.com/questions/4935632/parse-json-in-javascript and https://msdn.microsoft.com/en-us/library/cc836466(v=vs.85).aspx — Jaiprakash, Jun 23 '16 at 12:36
There is no JSON in this post. `myvar` holds a string that appears to be some JS code. In that code you have a call to a function to which you are passing a JS object literal. — JAAulde, Jun 23 '16 at 12:38

Pranav C Balan · Accepted Answer · 2017-01-04T14:37:58.193

1

Make it valid JSON first by removing myname( at beginning and ); at the end, use String#replace for that. After that parse the string using JSON.parse method and get the data you want.

var myvar = 'myname({    "country":{        "cities":[ {"id":"3", "population":"3700"},{"id":"5", "population":"3730"}]   } });';

console.log(JSON.parse(myvar.replace(/^\s*\w+\(|\);$/g, '')).country.cities);

edited Jan 04 '17 at 14:37

answered Jun 23 '16 at 12:38

Pranav C Balan

113,687
23
165
188

score 1 · Answer 2 · answered Jun 23 '16 at 12:38

this is not a json object, it contains a function, JSON is only a javascript object.

to get this you might need to use eval, although i dont recommend.

var myvar = 'myname({    "country":{        "cities":[ {"id":"3", "population":"3700"},{"id":"5", "population":"3730"}]   } });';

function myname(jsonObj) {
  console.log(jsonObj)
}

eval(myvar); //will log the whole object.

score 1 · Answer 3 · answered Jun 23 '16 at 12:40

1

Change your json to

var myvar = { "country":{ "cities":[ {"id":"3", "population":"3700"},{"id":"5", "population":"3730"}] } };

and you can get the cities as myvar.country["cities"]

answered Jun 23 '16 at 12:40

Pankaj Kumar

871
5
12

score 1 · Answer 4 · edited May 23 '17 at 11:53

JSON is valid JavaScript, but not all valid JavaScript is valid JSON.

As Nina pointed out in comments on the question, the string you've pasted in your question might be valid JavaScript, but it is not valid JSON.

Once you've corrected that problem, you can use this solution to parse your JSON:

var myvar = '{"country":{"cities":[{"id":"3", "population":"3700"},{"id":"5", "population":"3730"}]}}';
var theData = JSON.parse(myvar);

How to get citiesArr array of city objects from myvar?

Once you've used JSON.parse(...) to get back an object, you can use it like you'd normally use an object:

var myvar = '{"country":{"cities":[{"id":"3", "population":"3700"},{"id":"5", "population":"3730"}]}}';
var theData = JSON.parse(myvar);
var cities = theData.country.cities;
console.log(cities);

If you're not getting the string from a third party (like a file or a web server) then you may want to consider just building the object the normal way rather than trying to use strings of JSON at all:

var myvar = {"country":{"cities":[{"id":"3", "population":"3700"},{"id":"5", "population":"3730"}]}};

extract array from string that is a valid JSON

4 Answers4