edn-data is a JavaScript and TypeScript library that provides functionality to generate and parse data in the EDN format, as known from Clojure land.

• Support TypeScript with a strictly typed interface
• Support the rich EDN types
• Allow working with plain data in JavaScript, so everything can also be serialized to JSON
• Support modern JavaScript types such as Map, Set and bigint
• Support streaming EDN lists as standard Node stream in Node.js
• Have a solution that works in Node.js and in browsers

The number one reason is, your code wants to interact with data coming from Clojure.

But even outside Clojure EDN can be a compelling data format in a world where developers are stuck fighting YAML and complaining about JSON.

EDN has:

• less syntax than JSON
• built-in data types to represent maps, sets, keywords, dates, uuids, chars, bigints, ...
• multi-line strings
• tags and symbols to represent rich, custom data types
• comments
• streaming parsers
• no relevant whitespace

Install with:

npm install edn-data

By default parsing returns JSON-compatible data structures that can represent all of the rich EDN types.

There are options to make it easier to parse simpler types.

import { parseEDNString } from 'edn-data'

parseEDNString('{:key "value" :list [1 2 3]}')
// Returns:
{
  map: [
    [{ key: 'key' }, 'value'],
    [{ key: 'list' }, [1, 2, 3]],
  ],
}

parseEDNString(
  '{:key "value" :list [1 2 3]}',
  { mapAs: 'object', keywordAs: 'string' },
)
// Returns:
{
  key: 'value',
  list: [1, 2, 3],
}

EDN lists can be streamed value by value as standard Node.js Readable streams. This is not available in the browser.

import { parseEDNListStream } from 'edn-data/stream'

const s = parseEDNListStream()
s.write('(1 2 3)')
s.read() // 1
s.read() // 2
s.read() // 3

EDN is generated from plain JSON structures.

With toEDNString the same data structures parseEDNString returns can be turned to valid strings, and they represent a rich set of types.

For simple JavaScript types often toEDNStringFromSimpleObject might be the simpler use.

import { toEDNString, toEDNStringFromSimpleObject } from 'edn-data';

toEDNString({
  map: [
    [1, { key: 'keyword' }],
    [{ set: [1, 2] }, { char: 'a' }],
  ],
})
// Returns:
'{1 :keyword #{1 2} \a}'

toEDNStringFromSimpleObject({ first: 1, second: 2 })
// Returns:
'{:first 1 :second 2}'

The library is developed driven by its tests.

Verify them using

npm test

For continuous development use

npm run test:watch

Ensure the code formatting with

npm run fix

CI verifies tests and creates npm releases for tags automatically.

1. Change the version in the package.json
2. Push a commit to master in the following form Release <version>
3. A Git tag will be created and the new version will be published to NPM

MIT