Node.js loop through nested Javascript object

Question

I want to have posts + attachments from Facebook so I can create a list of posts. The problem is that I want to put attributes: id, message and any attachment in a array for every post feed. I'm not sure whether I need to iterate objects inside a array or can I select the ID and get the related information.

Also I'm using async.waterfall() to get synchronous calls because I will make other calls that depend on the previous call.

I tried this to get the id, message and src url of attachment:

var async = require("async");
var graph = require('fbgraph');

async.waterfall([
    getFeed,
    getPostPicture,
], function (err, result) {
});
function getFeed(callback) {
    graph.get("/.../feed" + "?fields=message,attachments&access_token=APPID|APPSECRET", function(err, res) {
        callback(null, res);
    });
}
function getPostPicture(arg1, callback) {

    var feedData = arg1.data;
    for(var i in feedData)
    {
        var id = feedData[i].id;
        var message = feedData[i].message;
        var feedAttachment = feedData[i].attachments

        for (var j in feedAttachment)
        {
            var attachment = feedAttachment.data;
            var attachmentURL = attachment[i].src;
            for (var j in attachmentURL)
            {
                var attachmentURL = feedAttachment.src;
            }
        }
    }
        console.log(attachment);
}

Above will output:

[ { description: 'post message 1',
    media: { image: [Object] },
    target:
     { id: '...',
       url: 'https://www.facebook.com/.../photos/a............/.../?type=3' },
    title: 'Timeline Photos',
    type: 'photo',
    url: 'https://www.facebook.com/.../photos/a............/.../?type=3' } ]

Below is the response where I first called graph.get in the source code

and I need { data -> [message, id, attachments -> data[src] ]}

{
  "data": [
    {
      "message": "post message 1",
      "id": "..._...",
      "attachments": {
        "data": [
          {
            "description": "picture 1",
            "media": {
            "image": {
            "height": 256,
            "src": "https://scontent.xx.fbcdn.net/v/t1.0-9/..._..._..._n.png?oh=...&oe=...",
            "width": 256
          }
        },
        "target": {
          "id": "...",
          "url": "https://www.facebook.com/.../photos/a............/.../?type=3"
        },
        "title": "Timeline Photos",
        "type": "photo",
        "url": "https://www.facebook.com/.../photos/a............./..../?type=3"
       }
      ]
     }
    },
    {
      "message": "Test status update 123",
      "id": "..._..."
    }
  ],
  "paging": {
  "previous": "https://graph.facebook.com/v2.8/.../feed?fields=message,attachments&format=json&since=...&access_token=...&limit=25&__paging_token=enc_...&__previous=1",
  "next": "https://graph.facebook.com/v2.8/.../feed?fields=message,attachments&format=json&access_token=...&limit=25&until=...&__paging_token=enc_..." 
  }
}

Answer 1

When you are using the for loop in getPostPicture function, the i variable is actually the element in the array feedData, so you have to i.id or i.attachments and i.message. Also I think since you are using same j in 2 loops with one nested inside the other, it also won't work properly, so you might have to change that also, and explain you question with the kind of output you are expecting.