Time stripped away from date-time query parameter

A time part is stripped away from date-time query parameters when using typescript-angular generator version 7.1.0 and type mapping "DateTime": "Date".

The problem points to https://github.com/OpenAPITools/openapi-generator/blob/f834519aebf8a565b1be768e67b1bd0aa8242b25/modules/openapi-generator/src/main/resources/typescript-angular/api.service.mustache#L135C19-L135C135 where .substring(..) is added if isDateTime property is falsy.

httpParams = httpParams.append(key, (value as Date).toISOString(){{^isDateTime}}.substring(0, 10){{/isDateTime}});

Apparently, isDateTime property does not get set on whether the format is date or date-time as my schema looks as following:

"/api/notification/unseen": {
      "get": {
        "tags": ["notification-controller"],
        "operationId": "getAllUnseen",
        "parameters": [{ "name": "since", "in": "query", "required": false, "schema": { "type": "string", "format": "date-time" } }],
        "responses": {
          "404": { "description": "Not Found", "content": { "*/*": { "schema": { "$ref": "#/components/schemas/CustomErrorResponse" } } } },
          "200": {
            "description": "OK",
            "content": {
              "application/json": { "schema": { "type": "array", "items": { "$ref": "#/components/schemas/NotificationDTO" } } }
            }
          }
        }
      }
    }

but .substring(0, 10) is appended to generated services.

A temporary solution is to add "isDateTime": true to additionalProperties and always opt for not stripping the time part.

{
  "$schema": "node_modules/@openapitools/openapi-generator-cli/config.schema.json",
  "generator-cli": {
    "version": "7.1.0",
    "generators": {
      "api": {
        "...
        "additionalProperties": {
          "ngVersion": "15.2.9",
          ...,
          "isDateTime": true
        },
        "typeMappings": {
          "DateTime": "Date"
        }
      }
    }
  }
}

Start with modules/openapi-generator/src/main/resources/typescript-angular/api.service.mustache around the query-parameter serialization shown in the issue, then trace how isDateTime is populated for the date-time schema and the DateTime type mapping. Generate the typescript-angular client from the provided schema and confirm that the since parameter preserves its time component instead of applying substring(0, 10).