[TypeScript] Configurable Date type mapping

Description

Feature request to be able to configure the Date type mapping to use string instead of Javascript Date.

As of v2.3.0, codegen is doing the correct default behavior of translating a swagger date-time to a Javascript Date object. However, we all know that JS Date is deeply flawed, only really working for UTC. To do real date and time work, a 3rd party library such as js-joda must be used. If the APIs take the ISO 8601 format on the wire and put them into a Date object though, information is already lost.

Swagger-codegen version

2.3.0

Related issues

#4812

Suggest a Fix

I'm not sure how to do configuration options. Currently, I'm forcing this with a modified source code:

@@ -42,7 +42,7 @@ public class TypeScriptAngular2ClientCodegen extends AbstractTypeScriptClientCod
         modelTemplateFiles.put("model.mustache", ".ts");
         apiTemplateFiles.put("api.service.mustache", ".ts");
         languageSpecificPrimitives.add("Blob");
-        typeMapping.put("Date","Date");
+        typeMapping.put("Date","string");
         typeMapping.put("file","Blob");
         apiPackage = "api";
         modelPackage = "model";

Start in TypeScriptAngular2ClientCodegen at the typeMapping entry for Date, then inspect how this generator exposes configuration options. Define a configurable mapping while preserving Date as the default, and verify that selecting string changes generated model types without changing the default behavior.