JSON: JSON Schema Nullable Enum Flag Tool

Description

Parse enumJson as a nonempty array, then return its length and whether any value is literal null.

A JSON Schema keyword expresses one constraint on an instance. Required-list membership, property naming, numeric bounds, and enum contents are distinct checks within a larger schema.

Parse enumJson as a nonempty array, then return its length and whether any value is literal null.

When to use this tool

Use JSON: JSON Schema Nullable Enum Flag when you need one explicit schema-keyword or membership component.

How to use the tool and how it works

Enter enumJson. Use the units and conventions below.
Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
Read result. Expand result to inspect the returned fields.

Parse enumJson as a nonempty array, then return its length and whether any value is literal null.^[1]

Input field	Meaning and units	Accepted input
enumJson	Enum Json	Required. Text. Implementation limit: 8192 Unicode code points and 16384 UTF-16 code units.

Output field	Interpretation	Returned shape
result	Result	Required. Object.
result.containsNull	Contains Null	Calculated result member: boolean.
result.enumSize	Enum Size	Calculated result member: number.

json

{
  "input": {
    "enumJson": "[\"x\",null]"
  },
  "output": {
    "result": {
      "containsNull": true,
      "enumSize": 2
    }
  }
}

Limitations and assumptions

Duplicates are counted and not rejected; this inspects one enum representation rather than a complete JSON Schema.
Outputs are nested inside result. Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.

Alternative or Complementary methods

Validate the complete schema and instance using the intended dialect before treating a local check as conformance.

References

Calculation and input contract: json/json-schema-nullable-enum-flag — tool.io

Similar or alternative tools

JSON: JSON Scalar Type Tag
Parse valueJson, reject arrays and objects, and return null, boolean, number, or string as the scalar type.
JSON: JSON Empty String Versus Missing Tag
Parse objectJson as an object and classify the literal key as missing, empty-string, null, or other using own-property presence before value checks.