how to query mongo db with values in the db?

Question

using angular2 with meteor, with the following data:

{ "_id" : "DxEraKtfYavoukdCK", "name" : "Aaron", "capacity" : 20,  "available_capacity" : 15, "location" : "1" }
{ "_id" : "yMhEggaGmS7iio9P4", "name" : "Benard", "capacity" : 20,  "available_capacity" : 20, "location" : "2" }
{ "_id" : "TTD2wedGYWaLctJHt", "name" : "Candy", "capacity" : 50, "available_capacity" : 15, "location" : "3" }

1. how do i find workers with capacity - available_capacity > 10?

2. how do i find workers with available_capacity >= capacity?

Answer 1

1. how do i find workers with capacity - available_capacity > 10?

    db.collection('workers').find({"capacity": {$gt: 10}}).toArray(function (err, res) { if (err) throw err; console.log(res); }); 

2. how do i find workers with available_capacity >= capacity?

    db.collection('workers').aggregate( [ { $project: { _id: 1, name: 1, capacity:1, capacity_available: { $gte: $capacity}, location: 1 } } ] ); 

Update

I just ran out other tutorials. I think the concept will be the same

Q1

Workers = new Mongo.Collection('workers');

if (Meteor.isClient) {

  // This code only runs on the client
  angular.module('simple-todos',['angular-meteor']);

  angular.module('simple-todos').controller('TodosListCtrl', ['$scope', '$meteor',
    function ($scope, $meteor) {

      $scope.findWorkers = $meteor.collection( function() {
        return Workers.find({"capacity": {$gt: 10}});
      });

    }]);
}

Q2

I don't know aggregate gonna working here. Just guess

Workers = new Mongo.Collection('workers');

if (Meteor.isClient) {

  // This code only runs on the client
  angular.module('simple-todos',['angular-meteor']);

  angular.module('simple-todos').controller('TodosListCtrl', ['$scope', '$meteor',
    function ($scope, $meteor) {

      $scope.findWorkers = $meteor.collection( function() {
        return Workers.aggregate(
        [
           {
              $project:
               {
                 _id: 1,
                 name: 1,
                 capacity:1,
                 capacity_available: { $gte: $capacity},
                 location: 1
               }
           }
         ]
        );
      });
    }]);
}