Javascript : array.length returns undefined

javascript, jquery, json

Solution

Objects don't have a `.length` property.

A simple solution if you know you don't have to worry about `hasOwnProperty` checks, would be to do this:

Object.keys(data).length;

If you have to support IE 8 or lower, you'll have to use a loop, instead:

var length= 0;
for(var key in data) {
    if(data.hasOwnProperty(key)){
        length++;
    }
}

Problem

I have a set of data that is being passed on by the PHP's `json_encode` function. I'm using the jQuery `getJSON` function to decode it: ``` $.getJSON("url", function (data) { console.log(data); }); ``` The output looks like this in the console: ``` Object {1: Object, 2: Object, 3: Object, 4: Object, 5: Object, 6: Object, 7: Object, 8: Object, 9: Object, 10: Object} ``` I can access each array by using `data[1]`, `data[2]` etc, but to make it easier I thought of looping thought it so I can access all at once: ``` $.getJSON("url", function (data) { for (var i = 0, len = data.length; i < len; i++) { //do something } }); ``` However I can't get this to work because the `data.length` returns the value `undefined`. What is wrong and how can I fix it?

Original source