AngularJS checking if a field within an object array exists

Just use an AngularJS filter, these are exactly made for that purpose:

var results = $filter('filter')(array, {id : 3}, true);

results will contain an an array of object(s) (there might be more than one) with an attribute id equal to 3.

If the length of results is zero then, there was no element matching the filter.
If you know, there is only one possible result you may retrieve it directly with results[0].

The advantage of using a filter is that you can easily filter on multiple attribute values by extending the filter expression {id : 3}.

Cheers,

This is more a js problem than an angular one. If you are using a library like lodash this is pretty straightforward :

_.findWhere(array, {'id': 3})

In plain javascript this is not much complicated. Here is an EcmaScript 5 solution, that makes use of the function some :

array.some(function(elem) {
    return elem.id === 3;
});

Wonder, you are missing a , after id:3

It's more of a javaScript looping over an Array than an AngularJS way,

var array =  [{id:1, name:"foo"}, {id:2, name:"bar"}, {id:3, name:"september"}];

for(var i in array){
    if(array[i].id === 3){
         console.log("found 3");
        //do something here.
         }
}

You don't need lodash, even. Native javascript:

(array.filter(function(a) {return a.id === 3})

will return an array containing only the element whose id is 3 if there is one, or an empty array if not.

you can do it with plain JavaScript:

array.find(function(element){
    if(element.id == 3) return true;
})