Merge pull request #1874 from realm/cm/template-method

* Add support for creating template objects

CHANGELOG.md

@@ -1,3 +1,25 @@
+X.Y.Z Release notes
+=============================================================
+### Compatibility
+* Sync protocol: 24
+* Server-side history format: 4
+* File format: 7
+* Realm Object Server: 3.0.0 or later
+
+### Breaking changes
+* None.
+
+### Enhancements
+* Added `Realm.createTemplateObject(objectSchema)` (#1870).
+
+### Bug fixes
+* None.
+
+### Internals
+* Realm Core v5.6.2.
+* Realm Sync v3.5.5.
+
+
 2.9.0 Release notes (2018-6-19)
 =============================================================
 ### Compatibility
@@ -16,7 +38,8 @@
 * Fix incorrect documentation of the `shouldCompactOnLaunch` parameters.
 
 ### Internals
-* None.
+* Realm Core v5.6.2.
+* Realm Sync v3.5.5.
 
 
 2.8.5 Release notes (2018-6-18)

docs/realm.js

@@ -132,6 +132,15 @@ class Realm {
      */
     static automaticSyncConfiguration(user) {}
 
+    /**
+     * Creates a template object for a Realm model class where all optional fields are `undefined` and all required
+     * fields have the default value for the given data type, either the value set by the `default` property in the
+     * schema or the default value for the datatype if the schema doesn't specify one, i.e. `0`, false and `""`.
+     *
+     * @param {Realm~ObjectSchema} schema object describing the class
+     */
+    static createTemplateObject(objectSchema) {}
+
     /**
      * Closes this Realm so it may be re-opened with a newer schema version.
      * All objects and collections from this Realm are no longer valid after calling this method.

lib/extensions.js

@@ -126,6 +126,47 @@ module.exports = function(realmConstructor) {
                 callback(error);
             });
         },
+
+        createTemplateObject(objectSchema) {
+            let obj = {};
+            for (let key in objectSchema.properties) {
+
+                let type;
+                if (typeof objectSchema.properties[key] === 'string' || objectSchema.properties[key] instanceof String) {
+                    // Simple declaration of the type
+                    type = objectSchema.properties[key];
+                } else {
+                    // Advanced property setup
+                    const property = objectSchema.properties[key];
+
+                    // if optional is set, it wil take precedence over any `?` set on the type parameter
+                    if (property.optional === true) {
+                        continue;
+                    }
+
+                    // If a default value is explicitly set, always set the property
+                    if (property.default !== undefined) {
+                        obj[key] = property.default;
+                        continue;
+                    }
+
+                    type = property.type;
+                }
+
+                // Set the default value for all required primitive types.
+                // Lists are always treated as empty if not specified and references to objects are always optional
+                switch (type) {
+                    case 'bool': obj[key] = false; break;
+                    case 'int': obj[key] = 0; break;
+                    case 'float': obj[key] = 0.0; break;
+                    case 'double': obj[key] = 0.0; break;
+                    case 'string': obj[key] = ""; break;
+                    case 'data': obj[key] = new ArrayBuffer(0); break;
+                    case 'date': obj[key] = new Date(0); break;
+                }
+            }
+            return obj;
+        }
     }));
 
     // Add sync methods

lib/index.d.ts

@@ -620,6 +620,12 @@ declare class Realm {
      */
     static automaticSyncConfiguration(user?: Realm.Sync.User): string;
 
+    /**
+     * @param {Realm.ObjectSchema} object schema describing the object that should be created.
+     * @returns {T}
+     */
+    static createTemplateObject<T>(objectSchema: Realm.ObjectSchema): T;
+
     /**
      * Delete the Realm file for the given configuration.
      * @param {Configuration} config

tests/js/realm-tests.js

@@ -1256,6 +1256,38 @@ module.exports = {
         });
     },
 
+    testCreateTemplateObject: function() {
+        var realm = new Realm({schema: [
+            schemas.AllTypes,
+            schemas.DefaultValues,
+            schemas.TestObject,
+            schemas.LinkToAllTypes
+        ]});
+        realm.beginTransaction();
+
+        // Test all simple data types
+        let template = Realm.createTemplateObject(schemas.AllTypes);
+        TestCase.assertEqual(Object.keys(template).length, 7);
+        let unmanagedObj = Object.assign(template, { boolCol: true });
+        let managedObj = realm.create(schemas.AllTypes.name, unmanagedObj) ;
+        TestCase.assertEqual(managedObj.boolCol, true);
+
+        // Default values
+        unmanagedObj = Realm.createTemplateObject(schemas.DefaultValues);
+        TestCase.assertEqual(Object.keys(unmanagedObj).length, 10);
+        managedObj = realm.create(schemas.DefaultValues.name, unmanagedObj);
+        TestCase.assertEqual(managedObj.boolCol, true);
+        TestCase.assertEqual(managedObj.intCol, -1);
+        TestCase.assertEqualWithTolerance(managedObj.floatCol, -1.1, 0.000001);
+        TestCase.assertEqualWithTolerance(managedObj.doubleCol, -1.11, 0.000001);
+        TestCase.assertEqual(managedObj.stringCol, 'defaultString');
+        TestCase.assertEqual(managedObj.dateCol.getTime(), 1);
+        TestCase.assertEqual(managedObj.dataCol.byteLength, 1);
+        TestCase.assertEqual(managedObj.objectCol.doubleCol, 1);
+        TestCase.assertEqual(managedObj.nullObjectCol, null);
+        TestCase.assertEqual(managedObj.arrayCol[0].doubleCol, 2);
+    }
+
 
     // FIXME: reanble test
     /*