Regex match JSON Object keys

regex-match-json-fields.js

// via https://stackoverflow.com/questions/8750127/regex-for-parsing-single-key-values-out-of-json-in-javascript
const obj1 = {
  id: 1,
  'name.1': '123',
  address: {
    'address.1': 'Chicken Dinner Road, 69',
    'address.2': 'Psycho lane, 666',
  },
  'age.1': {
    'thisIsSomeCrazyJson.3': 10,
    age: 50,
  },
  types: [
    {
      id: 22,
      'name.name': '123',
      typeOption: {
        id: 1,
        'whoTFWroteThisJSON.2': '123',
      },
    },
    {
      id: 32,
      'name.1': '123',
    },
  ],
};

const obj2 = {
  Name: 'Humpty',
  Age: '18',
  Siblings: ['Dracula', 'Snow White', 'Merlin'],
  Posts: [
    {
      Title: 'How I fell',
      Comments: [
        {
          'User': 'Fairy God Mother',
          'Comment': "Ha, can't say I didn't see it coming",
        },
      ],
    },
  ],
};


function matchKeyDeep(input, pattern) {
  return Object.entries(input).reduce((nextInput, [key, value]) => {
    const isMatch = pattern.test(key);
    if (Array.isArray(value)) {
      const arrValue = value;
      let nextValue = arrValue.map((arrItem) => {
        if (typeof arrItem === 'object') {
          return matchKeyDeep(arrItem, pattern);
        }
        return arrItem;
      });
      if (!isMatch && Array.isArray(nextValue)) {
        nextValue = nextValue.filter((v) => (typeof v === 'object' && v !== null));
        if (nextValue.length === 0) return nextInput;
      }
      nextInput[key] = nextValue;
      return nextInput;
    }
    if (typeof value === 'object') {
      const recurse = matchKeyDeep(value, pattern);
      if (!isMatch && Object.keys(recurse).length === 0) {
        return nextInput;
      }
      nextInput[key] = recurse;
      return nextInput;
    }

    if (isMatch) {
      nextInput[key] = value;
    }

    return nextInput;
  }, {});
}

const res = matchKeyDeep(obj1, /\.\d/);
const res2 = matchKeyDeep(obj2, /Comment/);


console.log(res);
console.log(res2);