json/top-level-interop

Require the JSON top-level value to be an array or object

The first JSON specification, RFC 4627, only allowed an object or an array at the top of a document. Later ones allow any value, but some older parsers still reject a file that's just a string, a number, true, false, or null. Turn this rule on for files that such tools have to read.

Configure

Off by default. It needs an ESLint config that says which files are in the language:

eslint.config.js

import json from "@eslint/json";

export default [
  {
    files: ["**/*.json"],
    plugins: { json },
    language: "json/json",
    rules: { "json/top-level-interop": "error" },
  },
];

It also works with json/jsonc and json/json5.

Examples

Reported:

"app"

Not reported:

{ "name": "app" }

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