Parses out functions from pure JSON

parseFunction.js

let replacer = (key, value) => {  
  // if we get a function, give us the code for that function  
  if (typeof value === 'function') {    
    return value.toString();  
  }   
  return value;
} 

let reviver = (key, value) => {
  if (typeof value === 'string'
      && value.indexOf('function') === 0) {
    let functionTemplate = `(${value}).call(this)`;
    return new Function(functionTemplate);
  }
  return value;
};

reviver = (key, value) => {
  if (typeof value === 'string'
      && value.indexOf('function') === 0) {
    let functionTemplate = `(${value})`;
    return eval(functionTemplate);
  }
  return value;
}

const test = {
  foo: 'bar',
  baz: {
    raz: 45
  },
  func: function(a,b) {
    return a + b;
  }
}

console.log('OBJ', test);

const str = JSON.stringify(test, replacer);

console.log('STR', str);

const parsed = JSON.parse(str, reviver);

console.log('OBJ', parsed);

console.log('RES', parsed.func(1,2))