Impossible to omit an optional JSON request body (POST)

Q&A

• OS: macOS
• Browser: Firefox (or any)
• Version: 94.0.2
• Method of installation: npm/yarn
• Swagger-UI version: 3.18.2
• Swagger/OpenAPI version: Swagger 2.0

Content & configuration

Example Swagger/OpenAPI definition:

    "/api/users/{userId}/greetings" : {
      "post" : {
        "tags" : [
          "Users"
        ],
        "summary" : "Greets a user",
        "operationId" : "greetUsingPOST",
        "consumes" : [
          "application/json"
        ],
        "produces" : [
          "application/json"
        ],
        "parameters" : [
          {
            "name" : "userId",
            "in" : "path",
            "description" : "userId",
            "required" : true,
            "type" : "string"
          },
          {
            "in" : "body",
            "name" : "greeting",
            "required" : false,
            "schema" : {
              "$ref" : "#/definitions/Greeting"
            }
          }
        ],
        ...
      }

Swagger-UI configuration options:

            SwaggerUi({
                spec,
                domNode: el,
                swagger: "2.0",
                validatorUrl: null,
                docExpansion: "list",
                operationsSorter: compareOps,
                defaultModelExpandDepth: 5,
                defaultModelsExpandDepth: -1,
            })

Describe the bug you're encountering

I’d like to send a POST request with no request body. The request body is defined as optional, not required. The request body text field is prefilled, however, and whenever I delete the prefilled JSON, code in the page immediately inserts {}.

To reproduce...

Steps to reproduce the behavior:

1. Define a POST operation that takes an optional JSON request body.
2. Try to send a test request using swagger-ui that includes no request body.

Expected behavior

If I delete the JSON in the request body field and click “Execute”, then a POST request should be sent with no request body.

Screenshots

See above.

Additional context or thoughts

Thanks in advance for fixing! 😄

Reproduce the issue in Swagger UI 3.18.2 with a Swagger 2.0 POST operation whose JSON body parameter is optional, then trace the request-body editor behavior after its prefilled JSON is deleted. Done means clicking Execute sends the request without a body instead of inserting {}; add or update coverage for this scenario if the existing test structure provides a suitable place.