Preserving undefined that JSON.stringify otherwise removes

Question

How do I preserve undefined values when doing JSON.stringify(hash)?

Here\'s an example:

var hash = {
  \"name\" : \"boda\",
  \"email\" : undefined,
         


        

Answer 1

function stringifyWithUndefined(obj, space) {
  const str = JSON.stringify(obj, (key, value) => value === undefined ? '__undefined__' : value, space);
  return str.replace(/"__undefined__"/g, 'undefined');
}

Example:

const obj = {
  name: 'boda',
  email: undefined,
  country: 'africa'
};
console.log(stringifyWithUndefined(obj, 2));

Result:

{
  "name": "boda",
  "email": undefined,
  "country": "africa"
}