Question

I am looking to write a function which can look up a value based on a key and replace that value with another. The key is a tree from the start node of JSON. Here is the example.

var myData = {
    name : 'Dan',
    address: {
        city : 'Santa Clara',
                details : {
                   'prevhouse' : ''
                }
    }
}

Input to the function is a key tree. For eg, myData-address-details-prevhouse

When I pass this key with a new value, say ‘Texas’, the prevhouse value will get changed to the new value I am sending.

and new JSON will be

var myData = {
    name : 'Dan',
    address: {
        city : 'Santa Clara',
                details : {
                   'prevhouse' : 'Texas'
                }
    }
}

Here is what I wrote so far

var tree = key.split("-");

now the tree variable contains [“myData”,”address”, “details”,”prevhouse”]

I know that we can access the object using myData[tree[0]][tree[1]][tree[2]], but somehow not able to get it dynamic from parsed value.

how do we generate this dynamically since the length of the depth is not known till runtime.

Hope to get a help.

Answer 1

try with this code:

    var myData = {
        name: 'Dan',
        address: {
            city: 'Santa Clara',
            details: {
                prevhouse: ''
            }
        }
    };


    function setAttribute(obj, key, value) {
        var i = 1,
            attrs = key.split('-'),
            max = attrs.length - 1;

        for (; i < max; i++) {
            attr = attrs[i];
            obj = obj[attr];
        }

        obj[attrs[max]] = value;
        console.log('myData=', myData);

    }

    setAttribute(myData, "myData-address-details-prevhouse", "Texas");

here a working jsfiddle demo; see the console for the result