Stringify/parse object trees to/from JSON, with support for Map, Set and Date.

enhanceJSON offers drop-in replacements for JSON.parse and JSON.stringify, with identical signatures to those methods.

Run npm install --save enhancejson

enhanceJSON is used in the same way as you'd call JSON.stringify / JSON.parse.

Internally, it uses a custom replacer and reviver to handle Map, Set and Date values. Objects representing these types are identified by means of a __type field, which is added automatically. You should avoid using this key in your own data. Alternatively, you can specify a different key to use via the typeKey parameter on each method.

You can specify your own replacer and/or reviver, which will be used before (for replacers) or after (for revivers) the internal ones, when calling stringify or parse.

import * as enhanceJSON from 'enhancejson';

const data = {
  val1: 'test',
  map: new Map([[1, 'one'], [2, 'two']]),
  child: {
    sets: [
      new Set([1, 2, 3]),
      new Set(['a', 'b', 'c']),
    ],
    date: new Date('2024-04-06'),
  }
}

const strData = enhanceJSON.stringify(data);
const newData = enhanceJSON.parse(strData);

expect(newData).toEqual(data);

expect(typeof strData).toEqual('string');
expect(strData).toEqual(`{"val1":"test","map":{"__type":"M","v":[[1,"one"],[2,"two"]]},"child":{"sets":[{"__type":"S","v":[1,2,3]},{"__type":"S","v":["a","b","c"]}],"date":{"__type":"D","v":"2024-04-06T00:00:00.000Z"}}}`);

When the stringify function finds a Map, Set or Date value, it will output an object with a __type key of "M", "S" or "D", respectively. Another field on this same object will contain an array (for Map and Set) or string (for Date) representation of the original object.

When the parse function finds an object with this key, it assumes that it represents the corresponding data type, and will revive it as such.