[typscript][jquery] optional array query parameter is not generated correctly

Description

Defining an optional query parameter (configurationRevision in the shown yml) as array, the serialization seems to be wrong, and result in error:
"Cannot read property 'push' of undefined"

Serialized code (api/MeasurementsApi.ts):

if (configurationRevision) {
            configurationRevision.forEach((element: any) => {
                queryParameters['configurationRevision[]'].push(element);
            });
        }

Swagger-codegen version

I am using https://editor.swagger.io/ - Generate Client - typescript-jquery

Swagger declaration file content or url

swagger: '2.0'
info:
  description: Interface of REST Service for the Webclient
  version: 2.0.0
  title: REST Interface for Webclient
basePath: /api
tags:
  - name: configurations
paths:
  /measurements:
    get:
      tags:
        - measurements
      description: Returns all measurements
      parameters:
        - name: configurationId
          in: query
          description: Configuration ID
          required: false
          type: integer
          format: int32
        - name: configurationRevision[]
          in: query
          description: Configuration Revision
          required: false
          type: array
          items:
            type: integer
            format: int32
          collectionFormat: multi
      operationId: measurements
      produces:
        - application/json
      responses:
        '200':
          description: All available measurements
          schema:
            type: array
            items:
              type: integer
        '901':
          description: No valid licence

Command line used for generation

Steps to reproduce

Use above yml and generate typescript-jquery client code with: https://editor.swagger.io/

Related issues/PRs

Suggest a fix/enhancement

Create an emtpy array, to make push available.

if (configurationRevision) {
  queryParameters['configurationRevision[]'] = new Array<number>();
  configurationRevision.forEach((element: any) => {
    queryParameters['configurationRevision[]'].push(element);
  });
 }

[edit] insert collectionFormat: multi, change configurationRevision to configurationRevision[]

Reproduce the issue from the supplied Swagger YAML using the typescript-jquery generator and inspect the template responsible for api/MeasurementsApi.ts. Confirm the generated client safely handles the optional array query parameter, then regenerate and verify that the configurationRevision request no longer fails when values are supplied.