convert "converted" object string to JSON or Object

i've following problem and since i upgraded my prototypeJS framework.

the JSON parse is not able anymore to convert this string to an object.

"{empty: false, ip: true}"

previously in version 1.6 it was possible and now it needs to be a "validated" JSON string like

'{"empty": false, "ip": true}'

But how can i convert the 1st example back to an object?

JSON needs all keys to be quoted, so this:

"{empty: false, ip: true}"

is not a valid JSON. You need to preprocess it in order to be able to parse this JSON.

function preprocessJSON(str) {

    return str.replace(/("(\\.|[^"])*"|'(\\.|[^'])*')|(\w+)\s*:/g,
    function(all, string, strDouble, strSingle, jsonLabel) {
        if (jsonLabel) {
            return '"' + jsonLabel + '": ';
        }
        return all;
    });

}

(Try on JSFiddle) It uses a simple regular expression to replace a word, followed by colon, with that word quoted inside double quotes. The regular expression will not quote the label inside other strings.

Then you can safely

data = JSON.parse(preprocessJSON(json));

It makes sense that the json parser didn't accept the first input as it is invalid json. What you are using in the first example is javascript object notation. It's possible to convert this to an object using the eval() function.

var str = "({empty: false, ip: true})";
var obj = eval(str);

You should of course only do this if you have the guarantees the code you'll be executing is save. You can find more information about the json spec here. A json validator can be found here.

edit: Thai's answer above is probably a better solution

const dataWithQuotes = str.replace(/("(\\.|[^"])*"|'(\\.|[^'])*')|(\w+)\s*:/g, (all, string, strDouble, strSingle, jsonLabel) => {
  if (jsonLabel) {
    return `"${jsonLabel}": `;
  }
  return all;
});

return dataWithQuotes

similar solution as above , but updated with arrow functions.