Question

I have a map like data in JSON

var map =  {        
    level1 : {          
            x : {name:'level1 x' , },
            y : {name:'level1 y'}
    },
    level2 : {          
            x : {name:'level2 x'},
            y : {name:'level2 y'}
    }

}

I need to traverse through this data , i am getting the traverse path as an string

"level1 x name" , "level2 y name";

How can i parse through the JSON data from that string path..??

What i tried is ,

var path = "level1 x name".split(" ");
var pointer = map; // assuming it will take reference of map and change will cause to map also
 for (var i = 0, len = path.length; i < len; i++) {
   if(pointer){
      pointer = pointer[path[i]];
   }else{
     pointer = map[path[i]];
   } 
 }
 pointer = "level1 xx";

console.log(map);

But map data is not changing.. how to loop through with reference and change the value ..?

Answer 1

This is how you get your value:

var name = [map].concat("level1 x name".split(" ")).reduce(function(prev, curr) {
    return prev[curr];
});

console.log(name);

// -> 'level1 x'

JavaScript passes arguments by value, not by reference.

For your convenience I changed your code for you to acceomplish what you asked for:

var path = "level1 x name".split(" ");
var pointer = map; // assuming it will take reference of map and change will cause to map also
 for (var i = 0, len = path.length-1; i < len; i++) {
   if(pointer){
      pointer = pointer[path[i]];
   }else{
     pointer = map[path[i]];
   } 
 }
 pointer[path[path.length-1]] = "level1 xx";

console.log(map);