Add array as element of another Array

Question

I have an array like this

$scope.dogs = [
 { id: 1, breed: 'German Shepherd' }, 
 { id: 2, breed: 'Collie' }
]

And a second array like this:

$scope.owners = [
 { name: 'Mary', breedowned: 'German Shepherd' }, 
 { name: 'Bill', breedowned: 'German Shepherd' }, 
 { name: 'Bob', breedowned: 'Collie' }
]

I want to push the list of owners into the list of dogs like so basically creating:

$scope.dogs = [
 { id: 1, breed: 'German Shepherd', owners: [...] }
]

I tried to use forEach and push the owners into the dogs array, but it does not work.

 angular.forEach($scope.dogs, function (value, key) {
 for (x = 0; x < $scope.owners.length; x++) {
 if ($scope.owners[i].breedowned == value.breed) {
 $scope.dogs[key].owners.push($scope.owners[i])
 }
 }
 });

Thanks for any help!

Answer 1

If you don't want any form of dependency, just use Array.prototype.push.apply, this way:

Array.prototype.push.apply($scope.owners, $scope.dogs);

• agmcleod: Don't think that works though, because that would merge the first array into the second. The asker wants the owners pushed to an owners array on the dog itself.
• illeb: that's why i specified "If you don't want any form of dependency". The question was not clear at 100%.

Answer 2

You didnt mention any errors, but I see an issue with you missing var in front of the x in the for loop, and also owners is not initialized in the dog object. Here's a consistent nested loop solution:

angular.forEach($scope.dogs, function (dog) {
 angular.forEach($scope.owners, function (owner) {
 if (owner.breedowned == dog.breed) {
 dog.owners = dog.owners || []
 dog.owners.push(owner)
 }
 })
})

• BSmall: The problem is that I receive the dogs array from a call, so it is not initialized. If initialized, my original attempt works, but thanks. I'm going to try your solution.
• agmcleod: Yep that's perfectly okay, just explaining why it likely didnt work :)

Answer 3

Here a better solution that only goes through the owners array once and only through the dogs array once.

var tracker = $scope.owners.reduce(function(trackerObj, owner){
 var breedowned = owner.breedowned;
 trackerObj[breedowned] = trackerObj[breedowned] || [];
 trackerObj[breedowned].push(owner);
 return trackerObj;
}, {});
$scope.dogs.forEach(function(dog){
 dog.owners = tracker[dog.breed];
});