Compare array with forEach items

Question

My app is using Pubnub and I'm retrieving chat history with the following code:

$scope.populateMessages = function() {       
        // Populate message history using jsapi (optional)
        PubNub.jsapi.history({
            channel: $scope.channel,
            count: 15,
            callback: function(payload) {
                payload[0].forEach(function(message) {
                $scope.messages.push(message);

                //message timetoken
                console.log(message.pn_apns.aps.timetoken);
            });
            $scope.messagesStatus = false;
            $scope.connectionStatus  = false;
            $scope.$apply();
            }
        }); 
    };

When my app is coming from the background I want check for new messages again. But when I run the code above I get duplicates. If I clear $scope.messages before I run the code above it is working only there is a load time.

So Wat I'm currently trying to do is check the current list of messages by retrieving the time tokens of the existing messages:

var div = $('.list');
var divs = $('.item .chatMessage');
var divArray = [];

for (var i = 0; i < divs.length; i += 1) {
    divArray.push(divs.attr('timetoken'));
}

//list of existing messages timetokens
console.log(divArray);

And I want to compare them with the new messages retrieved with the populateMessages function above. If a message timetoken already exist do nothing, if the timetoken is not existing add the message ($scope.messages.push(message);)

http://stackoverflow.com/questions/9229645/remove-duplicates-from-javascript-array — Preston Van Loon, Jul 20 '15 at 13:30

score 1 · Answer 1 · answered Jul 20 '15 at 13:30

1

If you are using a library like lodash or underscore you can do

$scope.messages = _.uniq($scope.messages, function(msg) { return msg.timetoken;})

answered Jul 20 '15 at 13:30

Avraam Mavridis

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Compare array with forEach items

1 Answers1