[typescript-angular] docker image and jar versions mismatch. missed null check

Description

All those

swaggerapi/swagger-codegen-cli:latest
swaggerapi/swagger-codegen-cli:v2.3.1
swaggerapi/swagger-codegen-cli:v2.3.0

docker images don't match

http://repo1.maven.org/maven2/io/swagger/swagger-codegen-cli/2.3.1/swagger-codegen-cli-2.3.1.jar

behaviour.

Function generated by docker image (any version):

public createItem(q?: string, body: ItemModel, observe: any = 'body', reportProgress: boolean = false): Observable<any> {
  let queryParameters = new HttpParams({encoder: new CustomHttpUrlEncodingCodec()});
  if (q !== undefined && q !== null) {
    queryParameters = queryParameters.set('q', <any>q);
  }
  ....
}

Function generated by swagger-codegen-cli-2.3.1.jar:

public createItem(q?: string, body: ItemModel, observe: any = 'body', reportProgress: boolean = false): Observable<any> {
  let queryParameters = new HttpParams({encoder: new CustomHttpUrlEncodingCodec()});
  if (q !== undefined) {
    queryParameters = queryParameters.set('q', <any>q);
  }
  ....
}

As u can see, null check is missed in generated code.

Command line used for generation

• Docker image

docker pull swaggerapi/swagger-codegen-cli
docker run --rm -v \
    ${PWD}/src/app/core/swagger:/local swaggerapi/swagger-codegen-cli \
    generate \
    -i /local/json/swagger.json \
    -l typescript-angular \
    -o /local/generated/out

• jar

java -jar swagger-codegen-cli-2.3.1.jar generate -i src/app/core/swagger/json/swagger.json -l typescript-angular -o src/app/core/swagger/generated/out

Steps to reproduce

1. Use json file similar to this snippet

{
  "swagger": "2.0",
  "paths": {
    "/items": {
      "post": {
        "summary": "Create an Item",
        "description": "",
        "operationId": "createItem",
        "consumes": [
          "application/json;charset=UTF-8"
        ],
        "produces": [
          "application/json;charset=UTF-8"
        ],
        "parameters": [
          {
            "name": "q",
            "in": "query",
            "description": "***",
            "required": false,
            "type": "string"
          },
          {
            "in": "body",
            "name": "body",
            "required": false,
            "schema": {
              "$ref": "#/definitions/CreateItemModel"
            }
          }
        ],
        "responses": {
          "200": {
            "description": "successful operation",
            "schema": {
              "$ref": "#/definitions/Item"
            }
          }
        }
      }
    }
  }
}

2. Use commands above (or similar)
3. Ensure that one of those commands generates null check and the other does not

Start with the supplied Swagger JSON snippet and run both the Docker and swagger-codegen-cli-2.3.1.jar generation commands. Compare the generated TypeScript Angular output, especially the createItem query-parameter null check. Done means both generation paths produce matching output with the expected null check.