Get all Keys/Array keys in JSON parse Object?

Question

I have sample JSON like this

`{
  values:[{
    "name": "Base Url",
    "url": "https://kubemanagement-prod.kohls.com"
  },
  {
    "name": "Base Url newwww",
    "url": "https://batman.com"
  }]
}`

Currently when I add this paticular JSON to the lodash _.keys gives me the result ["0", "1"] which is basically the index of first and second object 0 and 1 .

What I exactly want is to retrieve all the keys of the JSON object including sub object properties as well. In this case ["values","0", "1","name","url"]

Does anyone knows a lodash method or a mechanism to retrieve all the keys given in complex JSON object to nth level?

language : Angular + Typescript

Answer 1

This function recursively gets the keys from an objects tree, using _.keys() and _.flatMap() and _.union() to combine lists of keys, and get only the unique values:

 const getAllKeys = obj => _.union( _.keys(obj), _.flatMap(obj, o => _.isObject(o) ? getAllKeys(o) : []) ) const arr = {"values": [{"name":"Base Url","url":"https://kubemanagement-prod.kohls.com"},{"name":"Base Url newwww","url":"https://batman.com"}]} const result = getAllKeys(arr) console.log(result) 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js"></script> 

And the same idea without lodash, using Object.values() and Array.flatMap() to iterate the current object (or array), and Array.concat() and a Set to make the keys unique:

 const getAllKeys = obj => [...new Set([].concat( Object.keys(obj), Object.values(obj).flatMap(o => typeof o === 'object' ? getAllKeys(o) : []) ))] const arr = {"values": [{"name":"Base Url","url":"https://kubemanagement-prod.kohls.com"},{"name":"Base Url newwww","url":"https://batman.com"}]} const result = getAllKeys(arr) console.log(result) 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js"></script> 

Without array indexes:

 const getAllKeys = obj => _.union( _.isArray(obj) ? [] : _.keys(obj), _.flatMap(obj, o => _.isObject(o) ? getAllKeys(o) : []) ) const arr = {"values": [{"name":"Base Url","url":"https://kubemanagement-prod.kohls.com"},{"name":"Base Url newwww","url":"https://batman.com"}]} const result = getAllKeys(arr) console.log(result) 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js"></script> 

Answer 2

You don't need lodash for this, Object.keys is sufficient. You just write a recursive function, writing to a Set , perhaps converting to array when you're done:

 const array = [ { "name": "Base Url", "url": "https://kubemanagement-prod.kohls.com" }, { "name": "Base Url newwww", "url": "https://batman.com" } ]; function addAll(set, entries) { for (const entry of entries) { set.add(entry); } return set; } function allKeys(obj/*: object|array*/, keys/*: Set<string>*/ = new Set()) { addAll(keys, Object.keys(obj)); for (const entry of Object.values(obj)) { if (entry && typeof entry === "object") { allKeys(entry, keys); } } return keys; } console.log([...allKeys(array)]); 

Or using the structure in your edit:

 const array = { values:[{ "name": "Base Url", "url": "https://kubemanagement-prod.kohls.com" }, { "name": "Base Url newwww", "url": "https://batman.com" }] } function addAll(set, entries) { for (const entry of entries) { set.add(entry); } return set; } function allKeys(obj/*: object|array*/, keys/*: Set<string>*/ = new Set()) { addAll(keys, Object.keys(obj)); for (const entry of Object.values(obj)) { if (entry && typeof entry === "object") { allKeys(entry, keys); } } return keys; } console.log([...allKeys(array)]); 

Answer 3

How about

 const arr = {"values": [{"name":"Base Url","url":"https://kubemanagement-prod.kohls.com"},{"name":"Base Url newwww","url":"https://batman.com"}]} let result1 = Object.keys(arr) // get the object keys which is "values" let result2 = Object.keys(arr[result1]); // get the keys of the object name "0,1" here let result3 = Object.keys(arr[result1][0]); // get property names of one object "name and url" here let resutltant = result1.concat(result2, result3) // "merge array" console.log(resutltant) 

Assuming that your object properties names will remain constant

Answer 4

If you use typescript why don't use Object.entries or Object.values to do that?

You need to add to tsconfig the next line:

lib: [ ...... "es2018", ]