javascript - How to get all keys with values from nested objects

Question

I'm looking for something kind of like Object.keys but that works for potentially nested objects. It also shouldn't include keys that have object/array values (it should only include keys with immediate string/number/boolean values).

Example A

Input

{
   "check_id":12345,
   "check_name":"Name of HTTP check",
   "check_type":"HTTP"
}

Expected output

[
  "check_id",
  "check_name",
  "check_type"
]

Object.keys would work for flat cases like this, but not for nested cases:

Example B

Input

{
   "check_id":12345,
   "check_name":"Name of HTTP check",
   "check_type":"HTTP",
   "tags":[
     "example_tag"
   ],
   "check_params":{
      "basic_auth":false,
      "params":[
        "size"
      ],
      "encryption": {
        "enabled": true,
      }
   }
}

Expected output

[
  "check_id",
  "check_name",
  "check_type",
  "check_params.basic_auth",
  "check_params.encryption.enabled"
]

Note that this does not include tags, check_params, check_params.params, or check_params.encryption since these values are arrays/objects.

The question

Is there a library that does this? How would you implement it so that it can work with any object, large and nested, or small?

Answer 1

You could use reduce like this:

const keyify = (obj, prefix = '') => 
  Object.keys(obj).reduce((res, el) => {
    if( Array.isArray(obj[el]) ) {
      return res;
    } else if( typeof obj[el] === 'object' && obj[el] !== null ) {
      return [...res, ...keyify(obj[el], prefix + el + '.')];
    }
    return [...res, prefix + el];
  }, []);

const input = {
   "check_id":12345,
   "check_name":"Name of HTTP check",
   "check_type":"HTTP",
   "tags":[
     "example_tag"
   ],
   "check_params":{
      "basic_auth":false,
      "params":[
        "size"
      ],
      "encryption": {
        "enabled": true,
        "testNull": null,
      }
   }
};

const output = keyify(input);

console.log(output);