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no-schema-enum

Disallow enum in settings JSON schema files; use oneOf with const, title, and an explicit type instead.

Examples​

Give string choices readable labels​

These are setting definitions within a schema/*.json file. Keep stored values stable while adding labels that can be translated.

Incorrect

{
  "type": "string",
  "enum": ["fit-to-width", "fit-to-height"]
}

Correct

{
  "type": "string",
  "oneOf": [
    { "const": "fit-to-width", "title": "Fit to width" },
    { "const": "fit-to-height", "title": "Fit to height" }
  ]
}

Declare the type of string choices​

Labels alone are not enough: the containing setting needs type for the editor to render string choices. This missing type can be fixed automatically.

Incorrect

{
  "oneOf": [
    { "const": "light", "title": "Light theme" },
    { "const": "dark", "title": "Dark theme" }
  ]
}

Correct

{
  "type": "string",
  "oneOf": [
    { "const": "light", "title": "Light theme" },
    { "const": "dark", "title": "Dark theme" }
  ]
}

Label numeric choices​

The rule also reports numeric enum arrays. Keep the numeric type and values when adding labels.

Incorrect

{
  "type": "integer",
  "enum": [2, 4, 8]
}

Correct

{
  "type": "integer",
  "oneOf": [
    { "const": 2, "title": "Two spaces" },
    { "const": 4, "title": "Four spaces" },
    { "const": 8, "title": "Eight spaces" }
  ]
}

Why​

With enum, users see stored values such as fit-to-width, and the schema cannot associate them with translatable labels. With oneOf, each title provides a readable, translatable label while const preserves the stored value.

String choices also need "type": "string" on the containing setting so the settings editor can render the control. The rule can add a missing type automatically.

Options​

This rule has no options.

Configuration​

This rule checks JSON files inside a schema/ directory. Configure jsonc-eslint-parser (v2) for those files:

import * as jsoncParser from 'jsonc-eslint-parser';
import jupyterPlugin from '@jupyter/eslint-plugin';

export default [
  {
    files: ['**/schema/*.json'],
    languageOptions: { parser: jsoncParser },
    plugins: { jupyter: jupyterPlugin },
    rules: {
      'jupyter/no-schema-enum': 'error'
    }
  }
];
Which schema values are checked?

The rule reports enum properties whose value is an array in JSON files directly inside a schema/ directory. It also reports a missing sibling type when every oneOf choice has a string const. It does not add types to numeric or mixed choices, and it does not check JSON files outside these schema directories.