polyfill to support JSON.stringify over JS Maps

map.toJSON.js

// 1 August 2023
// map.toJSON
// when you absolutely must serialize a map
// using JSON.stringify() which normally
// returns map: {}

Map.prototype.toJSON = function toJSON() {
  var map = {};
  for (var [k, v] of this.entries()) {
    map[k] = v;
  }
  return map;
}

/* test it out */

var o = { map: new Map };
o.map.set("KEY", 'VALUE');
o.map.set(12312312, 'asdfadfadsf');

console.log(o);
// { map: Map { KEY → "VALUE", 12312312 → "asdfadfadsf" } }

JSON.stringify(o, null, 2);
/*
'{
  "map": {
    "12312312": "asdfadfadsf",
    "KEY": "VALUE"
  }
}'
*/