AngularJS checking if an object has a specific value - angularjs

Question

I'm trying to avoid duplicates. If I send the same name (say, Jason) again, I don't want it to be added to the $scope.people for the second time. How can I check it before adding?
$scope.people = [
{
name : "Jason",
age : 26,
height : 176,
},
{
name : "Mark",
age : 34
height : 190
}
];
$scope.add = function(name,age,height) {
// How can I make sure that Jason or Mark won't get added again?
}
If it was a simple array, I would have solved it like below, but this is different.
$scope.add = function (name) {
if ($scope.people.indexOf(name) == -1) {
$scope.people.push(name);
}
};

Answer 1

You can use AngularJS equals like the following example will show you. This is the common AngularJS way to handle such kind of logic. Well, this solution will completly compare two object instead of only comparing one attribute of an object.
$scope.add = function(name, age, height) {
//init
var found = false;
//equal logic
angular.forEach($scope.people, function (people) {
if (angular.equals(people, {
name: name,
age: age,
height: height
})) {
found = true; //set found state
return; // break angular.forEach()
}
});
//proceed
if (!found) {
$scope.people.push({
name: name,
age: age,
height: height
});
}
};

Answer 2

I got this code snippet from an StackOverflow post which I can't find right now. But this should do the trick:
function unique(collection, keyname) {
var output = [],
keys = [];
angular.forEach(collection, function (item) {
var key = item[keyname];
if (keys.indexOf(key) === -1) {
keys.push(key);
output.push(item);
}
});
return output;
};
Usage:
$scope.people = unique(jsonArray, 'name');

Answer 3

$.grep might help you over here
var result = $.grep(people, function(e){ return e.name == x.name; });
result will be an array of matches so you will come to know is there any match or not.

Answer 4

you can use a $filter to easily find existing people like this
$scope.people = [{
name: "Jason",
age: 26,
height: 176,
}, {
name: "Mark",
age: 34,
height: 190
}];
$scope.add = function(name, age, height) {
if(doesntExist(name)){
$scope.people.push({name: name, age: age, height: height})
}
}
function doesntExist(name){
return $filter('filter')($scope.people, {name: name}).length === 0
}
working plunker
http://plnkr.co/edit/4z4ofqTMUH4rMzpoIsI5?p=preview