node.js loop through object array

Question

I'm trying to store multiple objects from an array as a variable. I really hope that makes sense.

So, I am able to store one element of the array in a variable.

var data = msg.payload.data;
msg.payload = data.observations[0].clientMac;
return msg;

But instead of just the MAC from key 0, I want to loop through each key, grab the mac, and store it in a new array. I'm just not sure how to do that.

Below is a sample of how the data is formatted:

    {
    "apMac" : "aa:bb:cc:11:22:33",
    "apFloors" : [],
    "apTags" : [],
    "observations" : [{
            "ipv4" : null,
            "location" : {
                "lat" : 5.73212614236217,
                "lng" : -5.01730431523174,
                "unc" : 1.5059361681363623,
                "x" : [],
                "y" : []
            }, 
            "seenTime" : "2015-09-30T10:59:01Z",
            "ssid" : null,
            "os" : null,
            "clientMac" : "bb:cc:dd:33:22:11",
            "seenEpoch" : 1443610741,
            "rssi" : 46,
            "ipv6" : null,
            "manufacturer" : "Hewlett-Packard"
        }
      ]
}

Why does your sample data not show .clientMac properties in it? — jfriend00
– jfriend00, Commented Oct 1, 2015 at 3:02

jfriend00 · Accepted Answer · 2015-10-01 03:27:16Z

2

data.observations is just an array of objects. There are many ways to iterate over an array. Here's one:

data.observations.forEach(function(item) {
    console.log(item.clientMac);
});

Or, if you want to create an array of them, you can do this:

var macs = data.observations.map(function(item) {
    return item.clientMac;
});
console.log(macs);     // an array of clientMac properties

You can see documentation for array.map() and array.forEach().

edited Oct 1, 2015 at 3:27

answered Oct 1, 2015 at 3:00

jfriend00

711k104 gold badges1.1k silver badges1k bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Gregory Iiams Over a year ago

Thank you! The other answers are correct; however your example worked out of the box. I'm thinking I should be able to build on what you shared to also add location and timestamp data.

Lior Ben Aharon · Accepted Answer · 2015-10-01 03:32:41Z

0

You can also write:

for( var item in data.observations){
 console.log(item.bla);
}

or

for(var index=0;index<data.observations.length;index++){
 console.log(data.observations[index].bla);
}

answered Oct 1, 2015 at 3:32

Lior Ben Aharon

1253 bronze badges

Collectives™ on Stack Overflow

node.js loop through object array

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related