[BUG] Can't pass data as a json for array of object in typescript-axios generator

[Kavan72]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

Cannot pass a data-type object as an array of items in a form using Axios. It works perfectly for a normal object, but it's not working as expected for a form.

openapi-generator version

7.0.1

OpenAPI declaration file content or url

openapi: 3.0.3
info:
  title: Backend
  version: 1.0.0
paths:
  /company:
    put:
      requestBody:
        required: true
        content:
          multipart/form-data:
            schema:
              $ref: '#/components/schemas/UpdateCompanyDetails'
            encoding:
              industry:
                contentType: application/json
      responses:
        '204':
          description: The company data successfully updated

components:
  schemas:
    UpdateCompanyDetails:
      type: object
      properties:
        name:
          type: string
          description: the name of the company
        industry:
          type: array
          items:
            $ref: '#/components/schemas/Industry'
        currency:
          $ref: '#/components/schemas/Currency'
    Industry:
      type: object
      properties:
        id:
          type: integer
          description: The unique identifier of the industry
        name:
          type: string
          description: The name of the industry
    Currency:
      type: object
      properties:
        id:
          type: integer
          description: the unique identifier of the currency
        name:
          type: string
          description: the long name of the currency (i.e. US Dollars)

Suggest a fix

      {{#formParams}}
        {{#isArray}}
            if ({{paramName}}) {
          {{#isCollectionFormatMulti}}
            {{#contentType}}
                localVarFormParams.append('{{baseName}}', new Blob([JSON.stringify({{paramName}})], { type: "{{contentType}}", }));
            {{/contentType}}
            {{^contentType}}
              {{paramName}}.forEach((element) => {
                localVarFormParams.{{#multipartFormData}}append{{/multipartFormData}}{{^multipartFormData}}set{{/multipartFormData}}('{{baseName}}', element as any);
                })
            {{/contentType}}
          {{/isCollectionFormatMulti}}
          {{^isCollectionFormatMulti}}
              localVarFormParams.{{#multipartFormData}}append{{/multipartFormData}}{{^multipartFormData}}set{{/multipartFormData}}('{{baseName}}', {{paramName}}.join(COLLECTION_FORMATS.{{collectionFormat}}));
          {{/isCollectionFormatMulti}}
            }
        {{/isArray}}
        {{^isArray}}
            if ({{paramName}} !== undefined) {
          {{^multipartFormData}}
              localVarFormParams.set('{{baseName}}', {{paramName}} as any);
          {{/multipartFormData}}
          {{#multipartFormData}}
            {{#isPrimitiveType}}
                localVarFormParams.append('{{baseName}}', {{paramName}} as any);
            {{/isPrimitiveType}}
            {{^isPrimitiveType}}
              {{#isEnumRef}}
                  localVarFormParams.append('{{baseName}}', {{paramName}} as any);
              {{/isEnumRef}}
              {{^isEnumRef}}
                  localVarFormParams.append('{{baseName}}', new Blob([JSON.stringify({{paramName}})], { type: "application/json", }));
              {{/isEnumRef}}
            {{/isPrimitiveType}}
          {{/multipartFormData}}
            }
        {{/isArray}}
      {{/formParams}}

Currently, I'm using a custom template to check if any 'contentType' is defined, and if so, pass it as a blob and send it like this.

localVarFormParams.append('industry', new Blob([JSON.stringify(industry)], { type: 'application/json' }))

Actual output vs Expected output

Actual output

                industry.forEach((element) => {
                    localVarFormParams.append('industry', element as any);
                })

Expected output

                localVarFormParams.append('industry', new Blob([JSON.stringify(industry)], { type: 'application/json' }))

[Kavan72]

@borsch can you help on this issue, i'm happy to contribute in this issue

[Ross-H-Projects]

Also observing this bug. Would be great to get multipart working like this as I suspect it will also fix the issue where an array of files cannot be used in a multipart schema def

[przem]

+1