sort-cloudformation-json

Inspired by https://github.com/keithamus/sort-package-json and https://github.com/azat-io/eslint-plugin-perfectionist

Zero-config CLI that sorts the keys of a CloudFormation JSON template alphabetically and recursively, rewriting the file in place.

• Recursively sorts every object's keys with a deterministic, locale-independent ordering (reproducible across machines).
• Never reorders array elements — order is meaningful in CloudFormation — but still sorts the keys of any objects nested inside arrays.
• Preserves the file's trailing newline and uses 2-space indentation.

Usage

Run directly with npx:

npx sort-cloudformation-json ./aws/infrastructure.json

Or wire it into a package.json script:

{
  "scripts": {
    "infrastructure:format": "sort-cloudformation-json ./aws/infrastructure.json"
  }
}

It takes a single argument: the path to the JSON file to sort in place.

Requirements

• Node.js 24+.

Development

The source lives in src/ and uses only erasable TypeScript syntax, so it runs directly on Node 24 via native type stripping — no loader required:

node src/cli.ts ./aws/infrastructure.json

npm run build   # compile to dist/ (JavaScript + type declarations) with tsc
npm run lint    # ESLint

AI

Written mostly by Claude Opus 4.8 at High effort.