Check existence of an element in a nested javascript object array

Question

I'm getting a Javascript object in the following format

{
"Alerts": [{
        "Name": "...",
        "Type": "Warning",
        "Message": "...",
        "Time": "..."
    },
    {
        "Name": "...",
        "Type": "Critical",
        "Message": "...",
        "Time": "..."
    },
    {
        "Name": "...",
        "Type": "Info",
        "Message": "...",
        "Time": "..."
    }]
}

How do I check if an alert of the type Critical exists anywhere in this array object I receive.

I am using angularjs.

Or lodash http://stackoverflow.com/questions/13789618/differences-between-lodash-and-underscore — Ben Heymink, Oct 20 '14 at 09:59
if(data.Alerts.filter(function pluck(a){return a[this]}, "Message").indexOf("Critical")!==-1){ alert("oh noes!");} — dandavis, Oct 20 '14 at 10:00

score 2 · Answer 1 · answered Oct 20 '14 at 10:00

2

You can do something like this

function find(arr, key, text){
    for(var i = arr.length; i--;){
        if(arr[i][key] === text) return i;
    }
    return -1;
}

Usage

var index = find(jsonObject.Alerts, "Type", "Critical")

answered Oct 20 '14 at 10:00

A1rPun

16,287
7
57
90

Kalhan.Toress · Accepted Answer · 2014-10-20T10:27:53.660

If you are searching angular kind of thing, Create a filter,

app.filter('checkCritical', function() {
    return function(input) {
         angular.forEach(input, function(obj) {
             if((obj.Type).toLowerCase() == 'critical') {
                return true;
             }
         });
         return false;
    };

})

use this filter inside the controller

in controller,

var exists = $filter("checkCritical").(Alerts);

dont forget to inject the $filter in to the controller

score 0 · Answer 3 · answered Oct 20 '14 at 10:01

If you have jQuery on the page.

var exists = $.grep(alerts, function (e) { return e.Type == 'Critical'; }).length > 0;

Note: alerts (as above) will be the array of alerts you have in your object there.

Reference:

http://api.jquery.com/jquery.grep/

score -1 · Answer 4 · answered Oct 20 '14 at 09:55

-1

You'll have to loop through each element of the array and check to see if any objects have 'Critical' as the Type property value.

answered Oct 20 '14 at 09:55

Ben Heymink

1,700
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Check existence of an element in a nested javascript object array

4 Answers4