Add support for aggregates on collections (#807) (#1350)

CHANGELOG.md

@@ -4,7 +4,7 @@ X.Y.Z Release notes
 * None
 
 ### Enhancements
-* None
+* Added aggregate functions `min()`, `max()`, `sum()`, and `avg()` to `Realm.Results` and `Realm.List` (#807).
 
 ### Bug fixes
 * Fixed port conflict between RN >= 0.48 inspector proxy and RPC server used for Chrome debugging (#1294).

docs/collection.js

@@ -174,6 +174,42 @@ class Collection {
     */
    indexOf(object) {}
 
+    /**
+     * Computes the minimum value of a property.
+     * @param {string} property - The name of the property.
+     * @throws {Error} If no property with the name exists or if property is not numeric/date.
+     * @returns {number} the minimum value.
+     * @since 1.12.1
+     */
+    min(property) {}
+
+    /**
+     * Computes the maximum value of a property.
+     * @param {string} property - The name of the property.
+     * @throws {Error} If no property with the name exists or if property is not numeric/date.
+     * @returns {number} the maximum value.
+     * @since 1.12.1
+     */
+    max(property) {}
+
+    /**
+     * Computes the sum of a property.
+     * @param {string} property - The name of the property.
+     * @throws {Error} If no property with the name exists or if property is not numeric/date.
+     * @returns {number} the sum.
+     * @since 1.12.1
+     */
+    sum(property) {}
+
+    /**
+     * Computes the average of a property.
+     * @param {string} property - The name of the property.
+     * @throws {Error} If no property with the name exists or if property is not numeric/date.
+     * @returns {number} the average value.
+     * @since 1.12.1
+     */
+    avg(property) {}
+
     /**
      * @see {@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach Array.prototype.forEach}
      * @param {function} callback - Function to execute on each object in the collection.

lib/browser/lists.js

@@ -32,6 +32,10 @@ createMethods(List.prototype, objectTypes.LIST, [
     'snapshot',
     'isValid',
     'indexOf',
+    'min',
+    'max',
+    'sum',
+    'avg',
     'addListener',
     'removeListener',
     'removeAllListeners',

lib/browser/results.js

@@ -31,6 +31,10 @@ createMethods(Results.prototype, objectTypes.RESULTS, [
     'snapshot',
     'isValid',
     'indexOf',
+    'min',
+    'max',
+    'sum',
+    'avg',
     'addListener',
     'removeListener',
     'removeAllListeners',

lib/index.d.ts

@@ -140,6 +140,34 @@ declare namespace Realm {
          */
         isValid(): boolean;
 
+        /**
+         * Computes the minimum value.
+         * @param  {string} property
+         * @returns number
+         */
+        min(property: string): number;
+
+        /**
+         * Computes the maximum value.
+         * @param  {string} property
+         * @returns number
+         */
+        max(property: string): number;
+
+        /**
+         * Computes the sum.
+         * @param  {string} property
+         * @returns number
+         */
+        sum(property: string): number;
+
+        /**
+         * Computes the average.
+         * @param  {string} property
+         * @returns number
+         */
+        avg(property: string): number;
+
         /**
          * @param  {string} query
          * @param  {any[]} ...arg

src/js_list.hpp

@@ -47,6 +47,7 @@ class List : public realm::List {
 
 template<typename T>
 struct ListClass : ClassDefinition<T, realm::js::List<T>, CollectionClass<T>> {
+    using Type = T;
     using ContextType = typename T::Context;
     using ObjectType = typename T::Object;
     using ValueType = typename T::Value;
@@ -74,6 +75,12 @@ struct ListClass : ClassDefinition<T, realm::js::List<T>, CollectionClass<T>> {
     static void is_valid(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
     static void index_of(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
 
+    // aggregate functions
+    static void min(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
+    static void max(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
+    static void sum(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
+    static void avg(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
+
     // observable
     static void add_listener(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
     static void remove_listener(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
@@ -92,6 +99,10 @@ struct ListClass : ClassDefinition<T, realm::js::List<T>, CollectionClass<T>> {
         {"sorted", wrap<sorted>},
         {"isValid", wrap<is_valid>},
         {"indexOf", wrap<index_of>},
+        {"min", wrap<min>},
+        {"max", wrap<max>},
+        {"sum", wrap<sum>},
+        {"avg", wrap<avg>},
         {"addListener", wrap<add_listener>},
         {"removeListener", wrap<remove_listener>},
         {"removeAllListeners", wrap<remove_all_listeners>},
@@ -115,6 +126,26 @@ void ListClass<T>::get_length(ContextType, ObjectType object, ReturnValue &retur
     return_value.set((uint32_t)list->size());
 }
 
+template<typename T>
+void ListClass<T>::min(ContextType ctx, FunctionType, ObjectType this_object, size_t argc, const ValueType arguments[], ReturnValue &return_value) {
+    compute_aggregate_on_collection<ListClass<T>>(AggregateFunc::Min, ctx, this_object, argc, arguments, return_value);
+}
+
+template<typename T>
+void ListClass<T>::max(ContextType ctx, FunctionType, ObjectType this_object, size_t argc, const ValueType arguments[], ReturnValue &return_value) {
+    compute_aggregate_on_collection<ListClass<T>>(AggregateFunc::Max, ctx, this_object, argc, arguments, return_value);
+}
+
+template<typename T>
+void ListClass<T>::sum(ContextType ctx, FunctionType, ObjectType this_object, size_t argc, const ValueType arguments[], ReturnValue &return_value) {
+    compute_aggregate_on_collection<ListClass<T>>(AggregateFunc::Sum, ctx, this_object, argc, arguments, return_value);
+}
+
+template<typename T>
+void ListClass<T>::avg(ContextType ctx, FunctionType, ObjectType this_object, size_t argc, const ValueType arguments[], ReturnValue &return_value) {
+    compute_aggregate_on_collection<ListClass<T>>(AggregateFunc::Avg, ctx, this_object, argc, arguments, return_value);
+}
+
 template<typename T>
 void ListClass<T>::get_index(ContextType ctx, ObjectType object, uint32_t index, ReturnValue &return_value) {
     auto list = get_internal<T, ListClass<T>>(object);

src/js_results.hpp

@@ -20,6 +20,7 @@
 
 #include "js_collection.hpp"
 #include "js_realm_object.hpp"
+#include "js_util.hpp"
 
 #include "results.hpp"
 #include "list.hpp"
@@ -49,6 +50,7 @@ class Results : public realm::Results {
 
 template<typename T>
 struct ResultsClass : ClassDefinition<T, realm::js::Results<T>, CollectionClass<T>> {
+    using Type = T;
     using ContextType = typename T::Context;
     using ObjectType = typename T::Object;
     using ValueType = typename T::Value;
@@ -76,6 +78,12 @@ struct ResultsClass : ClassDefinition<T, realm::js::Results<T>, CollectionClass<
 
     static void index_of(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
     
+    // aggregate functions
+    static void min(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
+    static void max(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
+    static void sum(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
+    static void avg(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
+
     // observable
     static void add_listener(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
     static void remove_listener(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
@@ -88,6 +96,10 @@ struct ResultsClass : ClassDefinition<T, realm::js::Results<T>, CollectionClass<
         {"filtered", wrap<filtered>},
         {"sorted", wrap<sorted>},
         {"isValid", wrap<is_valid>},
+        {"min", wrap<min>},
+        {"max", wrap<max>},
+        {"sum", wrap<sum>},
+        {"avg", wrap<avg>},
         {"addListener", wrap<add_listener>},
         {"removeListener", wrap<remove_listener>},
         {"removeAllListeners", wrap<remove_all_listeners>},
@@ -195,6 +207,26 @@ void ResultsClass<T>::get_length(ContextType ctx, ObjectType object, ReturnValue
     return_value.set((uint32_t)results->size());
 }
 
+template<typename T>
+void ResultsClass<T>::min(ContextType ctx, FunctionType, ObjectType this_object, size_t argc, const ValueType arguments[], ReturnValue &return_value) {
+    compute_aggregate_on_collection<ResultsClass<T>>(AggregateFunc::Min, ctx, this_object, argc, arguments, return_value);
+}
+
+template<typename T>
+void ResultsClass<T>::max(ContextType ctx, FunctionType, ObjectType this_object, size_t argc, const ValueType arguments[], ReturnValue &return_value) {
+    compute_aggregate_on_collection<ResultsClass<T>>(AggregateFunc::Max, ctx, this_object, argc, arguments, return_value);
+}
+
+template<typename T>
+void ResultsClass<T>::sum(ContextType ctx, FunctionType, ObjectType this_object, size_t argc, const ValueType arguments[], ReturnValue &return_value) {
+    compute_aggregate_on_collection<ResultsClass<T>>(AggregateFunc::Sum, ctx, this_object, argc, arguments, return_value);
+}
+
+template<typename T>
+void ResultsClass<T>::avg(ContextType ctx, FunctionType, ObjectType this_object, size_t argc, const ValueType arguments[], ReturnValue &return_value) {
+    compute_aggregate_on_collection<ResultsClass<T>>(AggregateFunc::Avg, ctx, this_object, argc, arguments, return_value);
+}
+
 template<typename T>
 void ResultsClass<T>::get_index(ContextType ctx, ObjectType object, uint32_t index, ReturnValue &return_value) {
     auto results = get_internal<T, ResultsClass<T>>(object);

src/js_types.hpp

@@ -29,6 +29,8 @@
 #include <realm/binary_data.hpp>
 #include <realm/string_data.hpp>
 #include <realm/util/to_string.hpp>
+#include <realm/util/optional.hpp>
+#include <realm/mixed.hpp>
 
 #if defined(__GNUC__) && !(defined(DEBUG) && DEBUG)
 # define REALM_JS_INLINE inline __attribute__((always_inline))
@@ -124,6 +126,8 @@ struct Value {
     static ValueType from_string(ContextType, const String<T> &);
     static ValueType from_binary(ContextType, BinaryData);
     static ValueType from_undefined(ContextType);
+    static ValueType from_timestamp(ContextType, Timestamp);
+    static ValueType from_mixed(ContextType, util::Optional<Mixed> &);
 
     static ObjectType to_array(ContextType, const ValueType &);
     static bool to_boolean(ContextType, const ValueType &);
@@ -424,5 +428,37 @@ inline std::string js_type_name_for_property_type(PropertyType type)
     return "<unknown>";
 }
 
+template<typename T>
+inline typename T::Value Value<T>::from_timestamp(typename T::Context ctx, Timestamp ts) {
+    return Object<T>::create_date(ctx, ts.get_seconds() * 1000 + ts.get_nanoseconds() / 1000000);
+}
+
+template<typename T>
+inline typename T::Value Value<T>::from_mixed(typename T::Context ctx, util::Optional<Mixed>& mixed) {
+    if (!mixed) {
+        return from_undefined(ctx);
+    }
+
+    Mixed value = *mixed;
+    switch (value.get_type()) {
+    case type_Bool:
+        return from_boolean(ctx, value.get_bool());
+    case type_Int:
+        return from_number(ctx, static_cast<double>(value.get_int()));
+    case type_Float:
+        return from_number(ctx, value.get_float());
+    case type_Double:
+        return from_number(ctx, value.get_double());
+    case type_Timestamp:
+        return from_timestamp(ctx, value.get_timestamp());
+    case type_String:
+        return from_string(ctx, value.get_string().data());
+    case type_Binary:
+        return from_binary(ctx, value.get_binary());
+    default:
+        throw std::invalid_argument("Value not convertible.");
+    }
+}
+
 } // js
 } // realm

src/js_util.hpp

@@ -22,11 +22,19 @@
 #include <sstream>
 #include <stdexcept>
 
+#include "object_schema.hpp"
 #include "shared_realm.hpp"
 
 namespace realm {
 namespace js {
 
+enum class AggregateFunc {
+    Min,
+    Max,
+    Sum,
+    Avg
+};
+
 template<typename T>
 class RealmDelegate;
 
@@ -75,5 +83,45 @@ static inline void validate_argument_count_at_least(size_t count, size_t expecte
     }
 }
 
+template<typename T>
+static inline void compute_aggregate_on_collection(AggregateFunc func, typename T::ContextType ctx, typename T::ObjectType this_object, size_t argc, const typename T::ValueType arguments[], typename T::ReturnValue &return_value) {
+    validate_argument_count(argc, 1);
+    std::string property_name = T::Value::validated_to_string(ctx, arguments[0]);
+
+    auto list = get_internal<typename T::Type, T>(this_object);
+
+    const ObjectSchema& object_schema = list->get_object_schema();
+    const Property* property = object_schema.property_for_name(property_name);
+    if (!property) {
+        throw std::invalid_argument(util::format("No such property: %1", property_name));
+    }
+
+    util::Optional<Mixed> mixed;
+    switch (func) {
+        case AggregateFunc::Min: {
+            mixed = list->min(property->table_column);
+            break;
+        }
+        case AggregateFunc::Max: {
+            mixed = list->max(property->table_column);
+            break;
+        }
+        case AggregateFunc::Sum: {
+            mixed = list->sum(property->table_column);
+            break;
+        }
+        case AggregateFunc::Avg: {
+            mixed = list->average(property->table_column);
+            break;
+        }
+        default: {
+            REALM_ASSERT(false && "Unknown aggregate function");
+            REALM_UNREACHABLE();
+        }
+    }
+
+    return_value.set(T::Value::from_mixed(ctx, mixed));
+}
+
 } // js
 } // realm

tests/js/list-tests.js

@@ -649,4 +649,199 @@ module.exports = {
             list.length;
         });
     },
+
+    testListAggregateFunctions: function() {
+        const NullableBasicTypesList = {
+            name: 'NullableBasicTypesList',
+            properties: {
+                list: {type: 'list', objectType: 'NullableBasicTypesObject'},
+            }
+        };
+
+        var realm = new Realm({schema: [schemas.NullableBasicTypes, NullableBasicTypesList]});
+        var object;
+
+        const N = 50;
+
+        var list = [];
+        for(var i = 0; i < N; i++) {
+            list.push({
+                intCol: i+1,
+                floatCol: i+1,
+                doubleCol: i+1,
+                dateCol: new Date(i+1)
+            });
+        }
+
+        realm.write(() => {
+            object = realm.create('NullableBasicTypesList', {list: list});
+        });
+
+        TestCase.assertEqual(object.list.length, N);
+
+        // int, float & double columns support all aggregate functions
+        ['intCol', 'floatCol', 'doubleCol'].forEach(colName => {
+            TestCase.assertEqual(object.list.min(colName), 1);
+            TestCase.assertEqual(object.list.max(colName), N);
+            TestCase.assertEqual(object.list.sum(colName), N*(N+1)/2);
+            TestCase.assertEqual(object.list.avg(colName), (N+1)/2);
+        });
+
+        // date columns support only 'min' & 'max'
+        TestCase.assertEqual(object.list.min('dateCol').getTime(), new Date(1).getTime());
+        TestCase.assertEqual(object.list.max('dateCol').getTime(), new Date(N).getTime());
+    },
+
+    testListAggregateFunctionsWithNullColumnValues: function() {
+        const NullableBasicTypesList = {
+            name: 'NullableBasicTypesList',
+            properties: {
+                list: {type: 'list', objectType: 'NullableBasicTypesObject'},
+            }
+        };
+
+        var realm = new Realm({schema: [schemas.NullableBasicTypes, NullableBasicTypesList]});
+        var object;
+        var objectEmptyList;
+
+        const N = 50;
+        const M = 10;
+
+        var list = [];
+        for(var i = 0; i < N; i++) {
+            list.push({
+                intCol: i+1,
+                floatCol: i+1,
+                doubleCol: i+1,
+                dateCol: new Date(i+1)
+            });
+        }
+
+        for(var j = 0; j < M; j++) {
+            list.push({
+                intCol: null,
+                floatCol: null,
+                doubleCol: null,
+                dateCol: null
+            });
+        }
+
+        realm.write(() => {
+            object = realm.create('NullableBasicTypesList', {list: list});
+            objectEmptyList = realm.create('NullableBasicTypesList', {list: []});
+        });
+
+        TestCase.assertEqual(object.list.length, N + M);
+
+
+        // int, float & double columns support all aggregate functions
+        // the M null valued objects should be ignored
+        ['intCol', 'floatCol', 'doubleCol'].forEach(colName => {
+            TestCase.assertEqual(object.list.min(colName), 1);
+            TestCase.assertEqual(object.list.max(colName), N);
+            TestCase.assertEqual(object.list.sum(colName), N*(N+1)/2);
+            TestCase.assertEqual(object.list.avg(colName), (N+1)/2);
+        });
+
+        // date columns support only 'min' & 'max'
+        TestCase.assertEqual(object.list.min('dateCol').getTime(), new Date(1).getTime());
+        TestCase.assertEqual(object.list.max('dateCol').getTime(), new Date(N).getTime());
+
+        // call aggregate functions on empty list
+        TestCase.assertEqual(objectEmptyList.list.length, 0);
+        ['intCol', 'floatCol', 'doubleCol'].forEach(colName => {
+            TestCase.assertUndefined(objectEmptyList.list.min(colName));
+            TestCase.assertUndefined(objectEmptyList.list.max(colName));
+            TestCase.assertEqual(objectEmptyList.list.sum(colName), 0);
+            TestCase.assertUndefined(objectEmptyList.list.avg(colName));
+        });
+
+        TestCase.assertUndefined(objectEmptyList.list.min('dateCol'));
+        TestCase.assertUndefined(objectEmptyList.list.max('dateCol'));
+    },
+
+    testListAggregateFunctionsUnsupported: function() {
+        const NullableBasicTypesList = {
+            name: 'NullableBasicTypesList',
+            properties: {
+                list: {type: 'list', objectType: 'NullableBasicTypesObject'},
+            }
+        };
+
+        var realm = new Realm({schema: [schemas.NullableBasicTypes, NullableBasicTypesList]});
+        var object;
+
+        const N = 5;
+
+        var list = [];
+        for(var i = 0; i < N; i++) {
+            list.push({
+                intCol: i+1,
+                floatCol: i+1,
+                doubleCol: i+1,
+                dateCol: new Date(i+1)
+            });
+        }
+
+        realm.write(() => {
+            object = realm.create('NullableBasicTypesList', {list: list});
+        });
+
+        TestCase.assertEqual(object.list.length, N);
+
+        // bool, string & data columns don't support 'min'
+        ['boolCol', 'stringCol', 'dataCol'].forEach(colName => {
+            TestCase.assertThrows(function() {
+                object.list.min(colName);
+            }
+        )});
+
+        // bool, string & data columns don't support 'max'
+        ['boolCol', 'stringCol', 'dataCol'].forEach(colName => {
+            TestCase.assertThrows(function() {
+                object.list.max(colName);
+            }
+        )});
+
+        // bool, string, date & data columns don't support 'avg'
+        ['boolCol', 'stringCol', 'dateCol', 'dataCol'].forEach(colName => {
+            TestCase.assertThrows(function() {
+                object.list.avg(colName);
+            }
+        )});
+
+        // bool, string, date & data columns don't support 'sum'
+        ['boolCol', 'stringCol', 'dateCol', 'dataCol'].forEach(colName => {
+            TestCase.assertThrows(function() {
+                object.list.sum(colName);
+            }
+        )});
+    },
+
+    testListAggregateFunctionsWrongProperty: function() {
+    var realm = new Realm({schema: [schemas.PersonObject, schemas.PersonList]});
+        var object;
+        var list;
+        realm.write(() => {
+            object = realm.create('PersonList', {list: [
+                {name: 'Ari', age: 10},
+                {name: 'Tim', age: 11},
+                {name: 'Bjarne', age: 12},
+            ]});
+        });
+
+        TestCase.assertThrows(function() {
+            object.list.min('foo')
+        });
+        TestCase.assertThrows(function() {
+            object.list.max('foo')
+        });
+        TestCase.assertThrows(function() {
+            object.list.sum('foo')
+        });
+        TestCase.assertThrows(function() {
+            object.list.avg('foo')
+        });
+
+    },
 };

tests/js/results-tests.js

@@ -455,6 +455,156 @@ module.exports = {
                 });
                 resolve = r;
             });
+        })
+    },
+
+    testResultsAggregateFunctions: function() {
+        var realm = new Realm({ schema: [schemas.NullableBasicTypes] });
+        const N = 50;
+        realm.write(() => {
+            for(var i = 0; i < N; i++) {
+                realm.create('NullableBasicTypesObject', {
+                    intCol: i+1,
+                    floatCol: i+1,
+                    doubleCol: i+1,
+                    dateCol: new Date(i+1)
+                });
+            }
         });
+
+        var results = realm.objects('NullableBasicTypesObject');
+        TestCase.assertEqual(results.length, N);
+
+        // int, float & double columns support all aggregate functions
+        ['intCol', 'floatCol', 'doubleCol'].forEach(colName => {
+            TestCase.assertEqual(results.min(colName), 1);
+            TestCase.assertEqual(results.max(colName), N);
+            TestCase.assertEqual(results.sum(colName), N*(N+1)/2);
+            TestCase.assertEqual(results.avg(colName), (N+1)/2);
+        });
+
+        // date columns support only 'min' & 'max'
+        TestCase.assertEqual(results.min('dateCol').getTime(), new Date(1).getTime());
+        TestCase.assertEqual(results.max('dateCol').getTime(), new Date(N).getTime());
+    },
+
+    testResultsAggregateFunctionsWithNullColumnValues: function() {
+        var realm = new Realm({ schema: [schemas.NullableBasicTypes] });
+
+        const N = 50;
+        const M = 10;
+
+        realm.write(() => {
+            for(var i = 0; i < N; i++) {
+                realm.create('NullableBasicTypesObject', {
+                    intCol: i+1,
+                    floatCol: i+1,
+                    doubleCol: i+1,
+                    dateCol: new Date(i+1)
+                });
+            }
+
+            // add some null valued data, which should be ignored by the aggregate functions
+            for(var j = 0; j < M; j++) {
+                realm.create('NullableBasicTypesObject', {
+                    intCol: null,
+                    floatCol: null,
+                    doubleCol: null,
+                    dateCol: null
+                });
+            }
+        });
+
+        var results = realm.objects('NullableBasicTypesObject');
+
+        TestCase.assertEqual(results.length, N + M);
+
+        // int, float & double columns support all aggregate functions
+        // the M null valued objects should be ignored
+        ['intCol', 'floatCol', 'doubleCol'].forEach(colName => {
+            TestCase.assertEqual(results.min(colName), 1);
+            TestCase.assertEqual(results.max(colName), N);
+            TestCase.assertEqual(results.sum(colName), N*(N+1)/2);
+            TestCase.assertEqual(results.avg(colName), (N+1)/2);
+        });
+
+        // date columns support only 'min' & 'max'
+        TestCase.assertEqual(results.min('dateCol').getTime(), new Date(1).getTime());
+        TestCase.assertEqual(results.max('dateCol').getTime(), new Date(N).getTime());
+
+        // call aggregate functions on empty results
+        var emptyResults = realm.objects('NullableBasicTypesObject').filtered('intCol < 0');
+        TestCase.assertEqual(emptyResults.length, 0);
+        ['intCol', 'floatCol', 'doubleCol'].forEach(colName => {
+            TestCase.assertUndefined(emptyResults.min(colName));
+            TestCase.assertUndefined(emptyResults.max(colName));
+            TestCase.assertEqual(emptyResults.sum(colName), 0);
+            TestCase.assertUndefined(emptyResults.avg(colName));
+        });
+
+        TestCase.assertUndefined(emptyResults.min('dateCol'));
+        TestCase.assertUndefined(emptyResults.max('dateCol'));
+    },
+
+    testResultsAggregateFunctionsUnsupported: function() {
+        var realm = new Realm({ schema: [schemas.NullableBasicTypes] });
+        realm.write(() => {
+            realm.create('NullableBasicTypesObject', {
+                boolCol: true,
+                stringCol: "hello",
+                dataCol: new ArrayBuffer(12),
+            });
+        });
+
+        var results = realm.objects('NullableBasicTypesObject');
+
+        // bool, string & data columns don't support 'min'
+        ['boolCol', 'stringCol', 'dataCol'].forEach(colName => {
+            TestCase.assertThrows(function() {
+                results.min(colName);
+            }
+        )});
+
+        // bool, string & data columns don't support 'max'
+        ['boolCol', 'stringCol', 'dataCol'].forEach(colName => {
+            TestCase.assertThrows(function() {
+                results.max(colName);
+            }
+        )});
+
+        // bool, string, date & data columns don't support 'avg'
+        ['boolCol', 'stringCol', 'dateCol', 'dataCol'].forEach(colName => {
+            TestCase.assertThrows(function() {
+                results.avg(colName);
+            }
+        )});
+
+        // bool, string, date & data columns don't support 'sum'
+        ['boolCol', 'stringCol', 'dateCol', 'dataCol'].forEach(colName => {
+            TestCase.assertThrows(function() {
+                results.sum(colName);
+            }
+        )});
+    },
+
+    testResultsAggregateFunctionsWrongProperty: function() {
+        var realm = new Realm({ schema: [ schemas.TestObject ]});
+        realm.write(() => {
+            realm.create('TestObject', { doubleCol: 42 });
+        });
+        var results = realm.objects('TestObject');
+        TestCase.assertThrows(function() {
+            results.min('foo')
+        });
+        TestCase.assertThrows(function() {
+            results.max('foo')
+        });
+        TestCase.assertThrows(function() {
+            results.sum('foo')
+        });
+        TestCase.assertThrows(function() {
+            results.avg('foo')
+        });
+
     }
 };