Fix transform of null primitive values

Author: sparebytes

src/TransformOperationExecutor.ts

@@ -57,12 +57,18 @@ export class TransformOperationExecutor {
             return newValue;
 
         } else if (targetType === String && !isMap) {
+            if (value === null || value === undefined)
+                return value;
             return String(value);
 
         } else if (targetType === Number && !isMap) {
+            if (value === null || value === undefined)
+                return value;
             return Number(value);
 
         } else if (targetType === Boolean && !isMap) {
+            if (value === null || value === undefined)
+                return value;
             return Boolean(value);
 
         } else if ((targetType === Date || value instanceof Date) && !isMap) {

test/functional/basic-functionality.spec.ts

@@ -507,6 +507,9 @@ describe("basic functionality", () => {
 
             @Type(type => String)
             lastVisitDate: string;
+
+            @Type(type => String)
+            signature?: null | string;
         }
 
         const date = new Date();
@@ -517,14 +520,16 @@ describe("basic functionality", () => {
         user.isActive = "1" as any;
         user.registrationDate = date.toString() as any;
         user.lastVisitDate = date as any;
+        user.signature = null as any;
 
         const fromPlainUser = {
             firstName: 321,
             lastName: 123,
             password: "123",
             isActive: "1",
             registrationDate: date.toString(),
-            lastVisitDate: date
+            lastVisitDate: date,
+            signature: null as null | string,
         };
 
         const fromExistUser = new User();
@@ -539,6 +544,7 @@ describe("basic functionality", () => {
             isActive: true,
             registrationDate: new Date(date.toString()),
             lastVisitDate: date.toString(),
+            signature: null,
         });
 
         const existUser = { id: 1, age: 27 };
@@ -553,6 +559,7 @@ describe("basic functionality", () => {
             isActive: true,
             registrationDate: new Date(date.toString()),
             lastVisitDate: date.toString(),
+            signature: null,
         });
         plainUser2.should.be.equal(existUser);
 
@@ -565,6 +572,7 @@ describe("basic functionality", () => {
             isActive: true,
             registrationDate: new Date(date.toString()),
             lastVisitDate: date.toString(),
+            signature: null,
         });
 
         const fromExistTransformedUser = plainToClassFromExist(fromExistUser, fromPlainUser, { strategy: "exposeAll" });
@@ -577,6 +585,7 @@ describe("basic functionality", () => {
             isActive: true,
             registrationDate: new Date(date.toString()),
             lastVisitDate: date.toString(),
+            signature: null,
         });
 
         const classToClassUser = classToClass(user, { strategy: "exposeAll" });
@@ -589,6 +598,7 @@ describe("basic functionality", () => {
             isActive: true,
             registrationDate: new Date(date.toString()),
             lastVisitDate: date.toString(),
+            signature: null,
         });
 
         const classToClassFromExistUser = classToClassFromExist(user, fromExistUser, { strategy: "exposeAll" });
@@ -603,6 +613,7 @@ describe("basic functionality", () => {
             isActive: true,
             registrationDate: new Date(date.toString()),
             lastVisitDate: date.toString(),
+            signature: null,
         });
     });
 
@@ -1681,4 +1692,4 @@ describe("basic functionality", () => {
 
     });
 
-});
+});