json parsing: GET elements if their exist in each in insertion - json

Question

I need to get all the data from my json FB file.
Some insertion for example, few fields have "likes" but others dont.
I need to check if the field "like" exists
An example of my data is this:
{
"userdata":
[
{
"id": "xxxxxxxxxxxxxxxxxxxx",
"from": {
"name": "my name",
"id": "xxxxxxxxxxxxxxxxxxxx"
},
"message": "Hello",
"actions": [
{
"name": "Comment",
"link": "https://www.facebook.com/"
},
{
"name": "Like",
"link": "https://www.facebook.com/"
}
],
"privacy": {
"description": "Friends",
"value": "ALL_FRIENDS",
"friends": "",
"networks": "",
"allow": "",
"deny": ""
},
"type": "status",
"status_type": "mobile_status_update",
"application": {
"name": "Graph API Explorer",
"id": "xxxxxxxxxxxxxxxxxxxx"
},
"created_time": "2013-12-25T15:22:43+0000",
"updated_time": "2013-12-25T15:22:43+0000",
**"likes"**: {
"data": [
{
"id": "xxxxxxxxxxxxxxxxxxxx",
"name": "friend1"
},
{
"id": "xxxxxxxxxxxxxxxxxxxx",
"name": "friend2"
}
],
"paging": {
"cursors": {
"after": "xxxxxxxxxxxxxxxxxxxx==",
"before": "xxxxxxxxxxxxxxxxxxxx=="
}
}
}
},
{
"id": "xxxxxxxxxxxxxxxxxxxx",
"from": {
"name": "name3",
"id": "xxxxxxxxxxxxxxxxxxxx"
},
"to": {
"data": [
{
"name": "my name",
"id": "xxxxxxxxxxxxxxxxxxxx"
}
]
},
"message": "hello again! ",
"actions": [
{
"name": "Comment",
"link": "https://www.facebook.com/xxxxxxxxxxxxxxxxxxxx"
},
{
"name": "Like",
"link": "https://www.facebook.com/xxxxxxxxxxxxxxxxxxxx"
}
],
"privacy": {
"value": ""
},
"type": "status",
"application": {
"name": "Facebook for iPad",
"namespace": "fbipad_",
"id": "xxxxxxxxxxxxxxxxxxxx"
},
"created_time": "2013-12-17T20:34:04+0000",
"updated_time": "2013-12-17T20:34:04+0000"
}
]
}
I use the following code but I get only the first insertion and not both because the second does not have the field "likes".
<script>
$(document).ready(function(){
});
$("#loaduserdata").click(function(){
$("#userdata tbody").html("");
$.getJSON("js.json", function(data){
$.each(data.userdata, function(i,user){
var tblRow =
"<tr>"
+"<td>FEED FROM: "+user.from.name+"</td>"
+"<td>MESSAGE: "+user.message+"</td>"
+"<td>created_time: "+user.created_time+"</td>"
+"<td>updated_time: "+user.updated_time+"</td>"
+ "<td>LIKES TO" + (typeof user.likes.data == "undefined" ? "" : user.likes.data.map(function(item) { return " "+item.name; }).join(", ")) + "</td>"
+"</tr>"
$(tblRow).appendTo("#userdata tbody");
});
}
);
});
</script>
HELP please.

Answer 1

You forgot to check if user.likes exists and only check for user.likes.data, but that check already throws an error because you try to access the property data on an undefined object.
function getLikesFromUser(user) {
if (user.likes && user.likes.data) {
return user.likes.data.map(function(item) {
return item.name;
}).join(", ");
} else {
return "";
}
}
Fixed Example on Plunker