flatted

A fast and minimal circular JSON parser.

Usable via CDN or as regular module.

// ESM
import {parse, stringify} from 'flatted/esm';

// CJS
const {parse, stringify} = require('flatted/cjs');

const a = [{}];
a[0].a = a;
a.push(a);

stringify(a); // [["1","0"],{"a":"0"}]

Compatibility

All ECMAScript engines compatible with Map, Set, Object.keys, and Array.prototype.reduce will work, even if polyfilled.

How does it work ?

While stringifying, all Objects, including Arrays, and strings, are flattened out and replaced as unique index. *

Once parsed, all indexes will be replaced through the flattened collection.

^{_{* represented as string to avoid conflicts with numbers}}

// logic example
var a = [{one: 1}, {two: '2'}];
a[0].a = a;
// a is the main object, will be at index '0'
// {one: 1} is the second object, index '1'
// {two: '2'} the third, in '2', and it has a string
// which will be found at index '3'

Flatted.stringify(a);
// [["1","2"],{"one":1,"a":"0"},{"two":"3"},"2"]
// a[one,two]    {one: 1, a}    {two: '2'}  '2'

Why not CircularJSON ?

If approved by the community, this project will be the core of CircularJSON V2.

The main reasons for having this software a part are:

• battle-testing against all complex cases before releasing CircularJSON V2
• provide a minimal parser without extra complexity needed by revivers and replacers
• give developers a way to compare the two formats (on average, with big structures, smaller with flatted)

Once satisfied by feedbacks and results, there will be a version of this project fully compatible with JSON API.