[Javascript] collectionFormat which is set to multi don't work when content type is multipart/form-data

Description

I want to have multi same parameter name when "multipart/form-data" is set to parameter type as "array" and collectionFormat is set to "multi".

Swagger-codegen version

latest

Swagger declaration file content or url

  consumes:
    - multipart/form-data
  parameters:
    - name: tags[]
      in: formData
      type: array
      collectionFormat: multi
      items:
        type: string

Command line used for generation

I use docker.

docker run --rm --name swagger_codegen_main_1 -w /gen -e GEN_DIR=/gen -v ~/docker/swagger-codegen:/gen -v /data/swagger_codegen:/local -v ~/.m2/repository:/root/.m2/repository --entrypoint /gen/docker-entrypoint.sh maven:3-jdk-7 generate -i /local/api.yaml -l javascript -o /local/out/javascript

Suggest a Fix

generated callApi in ApiClientjs

  exports.prototype.callApi = function callApi(path, httpMethod, pathParams,
      queryParams, headerParams, formParams, bodyParam, authNames, contentTypes, accepts,
      returnType, callback) {

    [snip]

    } else if (contentType == 'multipart/form-data') {
      var _formParams = this.normalizeParams(formParams);
      for (var key in _formParams) {
        if (_formParams.hasOwnProperty(key)) {
          if (this.isFileParam(_formParams[key])) {
            // file field
            request.attach(key, _formParams[key]);
          } else {
            request.field(key, _formParams[key]);
          }
        }
      }

    [snip]
  }

Should "request.field(key, _formParams[key])" be called multiple time when collectionFormat is multi and value type is array?

Start with the generated callApi implementation in ApiClientjs and the supplied multipart/form-data Swagger declaration. Trace how array form parameters with collectionFormat set to multi are normalized and passed to request.field. Done means the generated JavaScript client preserves repeated parameter names for these values.