Get property by path

Question

Lets say I have an following object:

var obj = {
    property: [{key:"value1"},{key:"value2"}]
}

And I have following string property[0].key

How can I obtain value2 using this string inside code?

Basicly I want to de something like this obj["property[1].key"]

If string have only dots, I can use following code:

function get_property_by_string(object, string){
    return string.split(".").reduce(function(obj, key) {
        return obj[key];
    }, object);
}

But with array this code doesn't work. Any suggestions?

@mithunsatheesh yes, but I have it as a string. I can't use use it this way obj["property[1].key"] — Grisha, Jul 29 '13 at 08:05
you can use eval(obj.property[1].key) but it's dangerous function — David, Jul 29 '13 at 08:08

score 2 · Accepted Answer · answered Jul 29 '13 at 08:09

2

Use can use the Eval() function which takes a string content and evaluate it as a command.

http://www.w3schools.com/jsref/jsref_eval.asp

answered Jul 29 '13 at 08:09

Tomer W

3,395
2
29
44

Is it any chance to avoid eval? Or is it only easy way? – Grisha Jul 29 '13 at 08:11
I guess you are concerned of Code injections? Can you specify your Goal, and constraints , maybe we can suggest an alternative way... – Tomer W Jul 29 '13 at 08:14
1

the other way is to parse the string... not that hard to do... but will take about 25 lines of code – Tomer W Jul 29 '13 at 08:16

score 0 · Answer 2 · answered Jul 29 '13 at 08:17

0

The fact that your property is stored as a string is not an issue. access the property of an object as such:

var obj = { 'key_a' : [{key:'value', otherkey: 'other value' }] },
    property = "key_a";

 obj[property][0].otherkey; // outputs "other value"

Avoid eval() if you can, it will only add overhead to your program and its usage is considered bad practice by some.

answered Jul 29 '13 at 08:17

jdog

174
6

the problem is that I don't know where is exactly this property located. I have only string. – Grisha Jul 29 '13 at 08:22
You don't need to know where the property of an Object is located, you access it via its key (a string), but perhaps I have misunderstood the question? :) – jdog Jul 29 '13 at 08:25

score 0 · Answer 3 · answered Jul 29 '13 at 08:18

You're creating 'property' as an array, so you should be able to access it directly. I've tested the following code locally on Chrome and it appears to work fine.

var obj = {
    property: [{key:"value1"},{key:"value2"}]
}

function test()
{
    alert(obj.property[0].key); // shows value1
    alert(obj.property[1].key); // shows value2
}

Get property by path

3 Answers3