added targetMap functionality

Author: Umed Khudoiberdiev

package.json

@@ -1,6 +1,6 @@
 {
   "name": "class-transformer",
-  "version": "0.1.0-beta.9",
+  "version": "0.1.0-beta.10",
   "description": "Proper decorator-based transformation / serialization / deserialization of plain javascript objects to class constructors",
   "license": "MIT",
   "readmeFilename": "README.md",

src/ClassTransformOptions.ts

@@ -1,3 +1,20 @@
+/**
+ * Allows to specify a map of Types in the object without using @Type decorator.
+ * This is useful when you have external classes.
+ */
+export interface TargetMap {
+
+    /**
+     * Target which Types are being specified.
+     */
+    target: Function;
+
+    /**
+     * List of properties and their Types.
+     */
+    properties: { [key: string]: Function };
+}
+
 /**
  * Options to be passed during transformation.
  */
@@ -32,4 +49,11 @@ export interface ClassTransformOptions {
      */
     ignoreDecorators?: boolean;
 
+    /**
+     * Target maps allows to set a Types of the transforming object without using @Type decorator.
+     * This is useful when you are transforming external classes, or if you already have type metadata for
+     * objects and you don't want to set it up again.
+     */
+    targetMaps?: TargetMap[];
+
 }

src/TransformOperationExecutor.ts

@@ -129,6 +129,10 @@ export class TransformOperationExecutor {
                         const options: TypeOptions = { newObject: newValue, object: value, property: propertyName };
                         type = metadata.typeFunction(options);
                         isSubValueMap = isSubValueMap || metadata.reflectedType === Map;
+                    } else if (this.options.targetMaps) { // try to find a type in target maps
+                        this.options.targetMaps
+                            .filter(map => map.target === targetType && !!map.properties[propertyName])
+                            .forEach(map => type = map.properties[propertyName]);
                     }
                 }