jquery json path

Question

I have the following json

{ "id": "0001", "type": "donut", "name": "Cake", "ppu": 0.55, "batters": { "batter": [ { "id": "1001", "type": "Regular" }, { "id": "1002", "type": "Chocolate" }, { "id": "1003", "type": "Blueberry" }, { "id": "1004", "type": "Devil's Food" } ] }, "topping": [ { "id": "5001", "type": "None" }, { "id": "5002", "type": "Glazed" }, { "id": "5005", "type": "Sugar" }, { "id": "5007", "type": "Powdered Sugar" }, { "id": "5006", "type": "Chocolate with Sprinkles" }, { "id": "5003", "type": "Chocolate" }, { "id": "5004", "type": "Maple" } ] }

I am trying to pass an xpath as a variable.

$(document).ready(function(){ var json_offset = 'topping.types' ... $.getJSON('json-data.php', function(data) { var json_pointer = data.json_offset; ... }); });

Which dosn't work. Can anyone help?

What doesn't work? What errors do you get?

Pekka
– Pekka

2011-09-05 08:57:27 +00:00
Commented Sep 5, 2011 at 8:57 — Pekka
– Pekka, Commented Sep 5, 2011 at 8:57

shesek · Accepted Answer · 2011-09-05 09:16:13Z

Something like that should work (I didn't actually test it, tho):

Object.getPath = function(obj, path) { var parts = path.split('.'); while (parts.length && obj = obj[parts.shift()]); return obj; } // Or in CoffeeScript: // Object.getPath = (obj, path) -> obj=obj[part] for part in path.split '.'; obj

Than, use it like that:

Object.getPath(data, json_offset)

However, unless the path is dynamic and you can't, you should simply use data.topping.types. Also, you referred to that path as "XPath", but XPath is a very different thing that has nothing to do with you're trying to do.

You welcome. I edited it a bit - there's no need to use another current variable, it can be done directly with obj, and I added a CoffeeScript version just for the heck of it

Mathias Bynens · Accepted Answer · 2011-09-05 09:03:14Z

// This won’t work: var json_offset = 'topping.types'; var json_pointer = data.json_offset; // Here, you attempt to read the `data` object’s `json_offset` property, which is undefined in this case. // This won’t work either: var json_offset = 'topping.types'; var json_pointer = data[json_offset]; // You could make it work by using `eval()` but that’s not recommended at all. // But this will: var offsetA = 'topping', offsetB = 'types'; var json_pointer = data[offsetA][offsetB];

Then you write a more generic solution like the one @shesek has in his answer :)

mauteri · Accepted Answer · 2012-07-27 13:09:20Z

Something like this works if it's dynamic.

var root = data; var json_offset = 'topping.types'; json_offset = json_offset.split('.'); for(var i = 0; i < path.length - 1; i++) { root = root[json_offset[i]]; } var json_pointer = root[path[json_offset.length - 1]];

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jquery json path

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