[BUG][typescript-fetch] Dictionaries with arrays of objects with custom types are not deserialized using custom deserializer

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator?
• 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

With dictionaries of strings to values, and the value being an array of objects of another custom type, these arrays of objects aren't run through the generated custom deserializer. This results in JSON not being turned into instances of objects properly.

With the typescript-fetch and the below OpenAPI specification, FooResponse.ts is generated and contains this:

return {

    'dictionaryToArrayOfTypes': json['dictionaryToArrayOfTypes'] == null ? undefined : json['dictionaryToArrayOfTypes'],
};

However, json['dictionaryToArrayOfTypes'] is taken directly and put into dictionaryToArrayOfTypes instead of looping over the values and calling BarFromJSON on them. If Bar in turn contains other types such as Date, they aren't deserialized into a Date object.

openapi-generator version

7.14.0

OpenAPI declaration file content or url

{
  "openapi" : "3.0.1",
  "info": {
    "title": "Test",
    "description": "Test.",
    "contact": {
      "name": "Foo",
      "url": "https://www.foo.com",
      "email": "support@foo.com"
    },
    "version": "v1"
  },
  "paths" : {
    "/api/Foo" : {
      "post" : {
        "operationId" : "Foo",
        "requestBody" : {
          "content" : {
            "application/json" : {
              "schema" : {
                "$ref" : "#/components/schemas/FooRequest"
              }
            }
          }
        },
        "responses" : {
          "default" : {
            "description" : "default response",
            "content" : {
              "application/json" : {
                "schema" : {
                  "$ref" : "#/components/schemas/FooResponse"
                }
              }
            }
          }
        }
      }
    }
  },
  "components" : {
    "schemas" : {
        "FooRequest" : {
          "type" : "object",
          "properties" : {
            "version" : {
              "type" : "integer",
              "format" : "int64"
            }
          }
          },
      "FooResponse" : {
        "type" : "object",
        "properties" : {
          "dictionaryToArrayOfTypes" : {
            "type" : "object",
            "additionalProperties" : {
              "type" : "array",
              "items" : {
                "$ref" : "#/components/schemas/Bar"
              }
            }
          }
        }
      },
      "Bar" : {
        "type" : "object",
        "properties" : {
          "someString" : {
            "type" : "string"
          }
        }
      }
    }
  }
}

Generation Details

docker run \
    --rm \
    -eJAVA_OPTS="-Dio.swagger.parser.util.RemoteUrl.trustAll=true -Dio.swagger.v3.parser.util.RemoteUrl.trustAll=true" \
    -v "${PWD}":/local \
    openapitools/openapi-generator-cli:v7.14.0 \
    generate \
    -i "swagger-spec.json" \
    -g typescript-fetch \
    --additional-properties=disallowAdditionalPropertiesIfNotPresent=false,enumPropertyNaming=UPPERCASE,supportsES6=true,validationAttributes=false,withInterfaces=true \
    -o "/local/generated-client"

Steps to reproduce

1. Run the above script with the specified specification.

Suggest a fix

The following happens for arrays of objects of a certain type when they aren't part of a dictionary, and something similar should probably also happen here:

'arrayOfTypes': json['arrayOfTypes'] == null ? undefined : ((json['arrayOfTypes'] as Array<any>).map(BarFromJSON)),

Start by reproducing the issue with the provided swagger-spec.json and typescript-fetch Docker command, then inspect the generated FooResponse.ts. Compare dictionaryToArrayOfTypes with the shown arrayOfTypes mapping. Done means dictionary values containing arrays of Bar objects invoke BarFromJSON for each item, including nested fields such as Date.