Converting A String Into a Nested JSON Object

Question

I was wondering if this was possible without eval (i hear it's evil).

var myString = 'myObject.property.subproperty';

and convert it to

var obj = {
    myObject: {
        property: {
            subproperty: {}
        }
    }
};

Been at this for 2 hours.

The val solution that I don't like:

I can do it with input string.

var myString = 'myObject.property.subproperty';
var nameTree = myString.split('.');
var evalString = '';
var myObj = {};
_.forEach(nameTree, function(value, key){

    if (key == 0) {
        evalString += 'myObj[' + value + '] = {};';
    } else {
        evalString += '[' + value + '] = {};';
    }
});

eval(evalString);

I get:

console.log(myObj);

// {myObject: {property:{subproperty:{}}}};

basically, given that input, you'll have to do it yourself. you can just use a self made function using split in a recursive fashion — Rooster
– Rooster, Commented Jul 9, 2014 at 17:35
I'm not sure what eval() has to do with your question because you can't even use it to make what you want from your input string. Anyway, here's a working demo: jsfiddle.net/jfriend00/Q9cWa using the same technique hugomg showed (who happens to type faster than I so posted an answer sooner). My version is put into a function. — jfriend00
– jfriend00, Commented Jul 9, 2014 at 17:40
@jfriend00 edited question to show the eval solution I mentioned. But it's evil. I burned it before it laid eggs. — Miguel Felipe Guillen Calo
– Miguel Felipe Guillen Calo, Commented Jul 9, 2014 at 19:48
OK, yep that's evil. That's even more complicated than not using eval(). — jfriend00
– jfriend00, Commented Jul 9, 2014 at 19:52

hugomg · Accepted Answer · 2014-07-09 18:07:47Z

3

The feature you can use to solve your problem is dynamic property access using string indexing. obj["foo"] is the same as obj.foo.

var properties = myString.split('.');
var obj = {};
var curr = obj;
for(var i=0; i<properties.length; i++){
    var next = {}
    curr[properties[i]] = next;
    curr = next;
}

edited Jul 9, 2014 at 18:07

answered Jul 9, 2014 at 17:35

hugomg

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1 Comment

Miguel Felipe Guillen Calo Over a year ago

This would give me a flat object. Or you pressed enter too fast?

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