How to find the position of matching brace in data?

I am new to Coding and at present i am working on NodeJs file system module.

I am working on a file which contains large data and that data stored as a string.

My problem is , I am not able to find the matching close brace and position of '}'.

{  // I know the index of '{'
  {
    {
    }
    {
    }
   }
   {
    {
    }
  }
 } // have to find position here.

Assuming that you want to have a program to do it!!!

Just compare one by one until the matching brace found. Code might be something similar to this (not tested) - 

    var string = "{{{}}}";

    var leftCurlyBraceIndex = 0, // index of the '{' to which you need to find the matching '}'
        rightCurlyBracesTobeIgnored = 0,
        rightCurlyBraceIndex = -1;

    for (var i = leftCurlyBraceIndex + 1, l = string.length; i < l; i++) {
       if (string[i] == "}") {
         if (rightCurlyBracesTobeIgnored == 0) {
            rightCurlyBraceIndex = i; break;
         } else {
            rightCurlyBracesTobeIgnored -= 1;
         }
       } else if (string[i] == "{"){
         rightCurlyBracesTobeIgnored += 1;
       }
    }

   alert(rightCurlyBraceIndex )


var str = '{{{}{}}{{}}}', matchBrace;   
matchBrace = function(str, i) {
    var index = 0, leftBraces = [], len;
    if(str.charAt(i) === '}') {
        return -1;
    }
    for(index = i, len = str.length; index < len; ++index) {
        if(str.charAt(index) === '{') {
            leftBraces.push('{');
        }
        if(str.charAt(index) === '}') {
            if(leftBraces.length === 1) {
                return index;
            }
            leftBraces.pop()
        }
     }
};