Package Exports

canonical-json
canonical-json/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (canonical-json) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

canonical-json - Deterministic JSON.stringify()

The goal of this module is to implement a version of JSON.stringify that returns a deterministic, canonical JSON format.

Canonical JSON means that the same object should always be stringified to the exact same string. JavaScript’s native JSON.stringify does not guarantee any order for object keys when serializing:

Properties of non-array objects are not guaranteed to be stringified in any particular order. Do not rely on ordering of properties within the same object within the stringification.

Source: https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/JSON/stringify

This module implements two alternative solutions to this problem:

stringify.js is based on Douglas Crockford's json2.js. It’s modified to serialize object keys in sorted order on the fly.
copy-stringify.js recursively creates a copy of the object with sorted keys, then passes it to native JSON.stringify.

By default, this package exports the index.js version.

Install

npm install canonical-json

Usage

ES Module

import stringify from 'canonical-json'

const obj = { b: 2, a: 1, c: { y: 0, x: 9 } }
console.log(stringify(obj)) // {"a":1,"b":2,"c":{"x":9,"y":0}}

CommonJS

const stringify = require('canonical-json')

console.log(stringify({ foo: 'bar', baz: 1 }))

Performance Comparison

Tested on Node.js (2022 MacBook Air M2):

native JSON.stringify: ~75 ms
canonical stringify.js: ~156 ms
copy & native copy-stringify.js: ~117 ms

Performance test source: test/performance.js

CLI

Use the canonical-json CLI to normalize JSON via stdin/stdout:

echo '{"b":2,"a":1}' | canonical-json > out.json

Test

npm test

License

MIT

canonical-json