Comma in serialization result

[piliugin-anton]

What version of Ajv are you using? Does the issue happen if you use the latest version?

Version: 8.11.0, JTD

Ajv options object

{
  coerceTypes: 'array',
  useDefaults: true,
  removeAdditional: true,
  uriResolver: fastUri,
  allErrors: false
}

JSON Schema

{
  "optionalProperties": {
    "test": {
      "type": "boolean"
    },
    "error": {
      "type": "string"
    }
  },
  "additionalProperties": false
}

Sample data

{ "error": "Something went wrong" }

Your code

const AjvJTD = require('ajv/dist/jtd')

const ajv = new AjvJTD({
  coerceTypes: 'array',
  useDefaults: true,
  removeAdditional: true,
  uriResolver: fastUri,
  allErrors: false
})
const serialize = ajv.compileSerializer(schema)
const result = serialize(object)

Serialized data (NOTICE COMMA)

{,"error":"Something went wrong"}

What results did you expect?

{"error":"Something went wrong"}

Are you going to resolve the issue?
Yes, look at #2028

[piliugin-anton]

I'm trying to achieve the result when serialized object could have some data on success or error

[craggy2593]

Also experiencing the same issue. With a schema of only optional properties, when the first optional property in the schema is missing from the object, the serialized output has a comma at the start, causing JSON validation issues downstream.

[epoberezkin]

That does look like a bug - the fix should be simple - PR is welcome, otherwise I’ll fix some time next month.

[piliugin-anton]

@epoberezkin Please have a look at #2028