Formatted string to js array

Question

I'm using an MVC app and my controller gets a string like this from mongodb:

str = "[{ title: 'My title', items: [{ name: 'item1', link: '#' }, { name: 'item2', link: '#' }] }]"

And I'm trying to use it in the view as a js Array, but I can't find any way to convert it.

Note that the array will have some sub arrays as items and some sub sub arrays, and so on.

Any help? Maybe I have to build the array inside my business layer instead of returning a string?

MVC is not an app. It's arcitectural pattern. Are you using ASP.NET MVC? — Vano Maisuradze, May 13 '15 at 19:02

Jeff · Answer 1 · 2015-05-13T19:06:35.730

4

the solution is JSON: have a look at the docs: http://www.w3schools.com/js/js_json.asp

And here is what you'd need to do:

var obj = JSON.parse(str);

This will give you a Javascript-Object (JSON=JavaScriptObjectNotation) which you then can access like that:

var firstTitle = obj[0].title;  // 'My title'
var itemsArrayOfFirstObject = obj[0].items;  // an Array of items
var linkOfForstItemInFirstObject = obj[0].items[0].link; // '#'

EDIT:

I oversaw that in your example the string is not in valid JSON-format

edited May 13 '15 at 19:06

answered May 13 '15 at 19:02

Jeff

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Unfortunately JSON.parse doesn't work here because the string is not valid JSON (note the lack of quotes around the keys). – ntdb May 13 '15 at 19:04
@ntdb so probably you should modify something at the back-end to provide valid JSON for later parsing. Also see http://stackoverflow.com/questions/24462658/convert-invalid-json-string-to-json – Eugene Naydenov May 13 '15 at 19:11

score 4 · Accepted Answer · answered May 13 '15 at 19:09

4

Knowing nothing else about the structure of your app, the easy way to convert that string into an object is using eval().

var object = eval("[{ title: 'My title', items: [{ name: 'item1', link: '#' }, { name: 'item2', link: '#' }] }]");

That said, NEVER use eval() on a string that you do not absolutely trust. It is very easily abused and exploited.

answered May 13 '15 at 19:09

ntdb

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Thanks @ntdb, that did the trick. I will anyways try to get the object in some other way from my app, just taking your warning not to abuse from eval(). – Kavesa May 13 '15 at 19:38

score 0 · Answer 3 · answered May 13 '15 at 19:44

Here's a function that will change the string to valid JSON, which is then returned as an object using JSON.parse():

function parse(str) {
  var t= '',
      special= '[]{} :,',
      qt;

  str= str.split('');

  for(var i = 0 ; i < str.length ; i++) {
    if((qt=str[i])==="'" || qt==='"') {
      do {
        t+= str[i++].replace("'",'"');
      } while(i < str.length && str[i]!==qt);
      t+= qt.replace("'",'"');
    }
    else if(special.indexOf(str[i])===-1) {
      t+= '"';
      do {
        t+= str[i++];
      } while(i < str.length && special.indexOf(str[i])==-1)
      t+= '"';
      i--;
    }
    else {
      t+= str[i];
    }
  }
  return JSON.parse(t);
} //parse

obj = parse("[{ title: 'My title', items: [{ name: 'item1', link: '#' }, { name: 'item2', link: '#' }] }]");
console.log(obj[0].items[1].name); //item2

I threw this together quickly, so I may be overlooking something. But it works with your example string.

Formatted string to js array

3 Answers3