What's the canonical way of disallowing empty strings as values?

Question

I have a number of string properties. How do I make sure those strings are not empty? Something more declarative than minLength: 1. Similar to required in HTML, whose somewhat equivalent for text inputs is minlength=1.

{
  "type": "object",
  "patternProperties": {
    "^(?:num|str|text|check|bool)[1-3]$": {
      "type": "string",
      "maxLength": 50
    }
  },
  "additionalProperties": false
}

Answer 1

The canonical way to do this is in fact by using minLength:

{
  "type": "object",
  "patternProperties": {
    "^(?:num|str|text|check|bool)[1-3]$": {
      "type": "string",
      "minLength": 1,
      "maxLength": 50
    }
  },
  "additionalProperties": false
}

You can always use reusable subschemas with $defs to create your own definition of an non-empty string. This also gives you a canonical and reusable name for it.

{
  "type": "object",
  "patternProperties": {
    "^(?:num|str|text|check|bool)[1-3]$": {
      "$ref": "#/$defs/nonEmptyStringOfMaxSize"
    }
  },
  "additionalProperties": false,
  "$defs": {
    "nonEmptyStringOfMaxSize": {
      "type": "string",
      "minLength": 1,
      "maxLength": 50
    }
  }
}