How to get all keys with values from nested objects

问题

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?

回答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 + '.')];
    } else {
      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);

回答2:

You could check the keys and iterate otherwise push the path to the result set.

function getKeys(object) {
    function iter(o, p) {
        if (Array.isArray(o)) { return; }
        if (o && typeof o === 'object') {
            var keys = Object.keys(o);
            if (keys.length) {
                keys.forEach(function (k) { iter(o[k], p.concat(k)); });
            }
            return;
        }
        result.push(p.join('.'));
    }
    var result = [];
    iter(object, []);
    return result;
}

var object = { 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 } } };

console.log(getKeys(object));

.as-console-wrapper { max-height: 100% !important; top: 0; }

回答3:

You can use for...in and create recursive function.

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

var keys = []
function getKeys(data, k = '') {
  for (var i in data) {
    var rest = k.length ? '.' + i : i

    if (typeof data[i] == 'object') {
      if (!Array.isArray(data[i])) {
        getKeys(data[i], k + rest)
      }
    } else keys.push(k + rest)
  }
}

getKeys(obj)
console.log(keys)

回答4:

Here's one way you can do it

const isPlainObject = x =>
  Object (x) === x && ! Array.isArray (x)

const formatKey = (...segments) =>
  segments .join ('.')

const deepKeys = (o, pre = [], acc = []) =>
  Object
    .keys (o)
    .reduce
      ( (acc, k) =>
          isPlainObject (o [k])
            ? [ ...acc, ...deepKeys (o [k], [ ...pre, k ], acc) ]
            : [ ...acc, formatKey (...pre, k) ]
      , []
      )

const data =
  { a: 1
  , b: 2
  , c: { d: 3
       , e: [ 4, 'a', 'b', 'c' ]
       , f: { g: 5
            , h: 6 
            } 
       }
  }
 
console .log (deepKeys (data))
// [ 'a'
// , 'b'
// , 'c.d'
// , 'c.e'
// , 'c.f.g'
// , 'c.f.h'
// ]

回答5:

Is this what you mean?

http://jsfiddle.net/robbiemilejczak/hfe12brb/1/

I couldn't do it with vanilla JS, and this is a pretty hacky solution that relies on lodash. Basically leverages lodashs _.forIn and _.isArray functions to iterate over an object. Also this will only go 1 layer deep, so objects inside of nested objects will be ignored. It does produce your expected output though, so I'd say it's a decent starting point.

来源：https://stackoverflow.com/questions/47062922/how-to-get-all-keys-with-values-from-nested-objects