CODEWITHSUNDEEP
javascript
Babak Abadkheir
Babak Abadkheir

Reputation: 2350

create nested object from string JavaScript

I have a string like this:

let user = "req.user.role"

is there any way to convert this as nested objects for using in another value like this?

let converted_string = req.user.role

I know I can split the user with user.split(".")

my imagination :

let user = "req.user.role".split(".")
let converted_string = user[0].user[1].user[2]

I found the nearest answer related to my question : Create nested object from query string in Javascript

Upvotes: 0

Views: 290

Answers (4)

maioman
maioman

Reputation: 18734

I'll take my shot at this:

let user = "req.user.role"

const trav = (str, o) => {
  const m = str.split('.')
  let res = undefined

  let i = 0
  while (i < m.length) {
    res = (res || o)[m[i]]
    if (!res) break
    i++
  }
  return res

}

const val = trav(user, {
  req: {
    user: {
      role: "admin"
    }
  }
})
console.log(val)

this function will traversed the passed in object for the entire length of the provided string.split "." list returning either a value or undefined.

Upvotes: 1

codeandcloud
codeandcloud

Reputation: 55200

Try this

let user = "req.user.role";
let userObj = user.split('.').reduceRight((obj, next) => ({
  [next]: obj
}), {});
console.log(userObj);

Or this, for old browsers

var user = "req.user.role";
var userArray = user.split('.'), userObj = {}, temp = userObj;
for (var i = 0; i < userArray.length; i++) {
  temp = temp[userArray[i]] = {};
}
console.log(userObj);

Upvotes: 2

Carsten Massmann
Carsten Massmann

Reputation: 28196

The function getvalue() will return the nested property of a given global variable:

var user="req.user.role";
var req={user:{role:"admin"}};

function getvalue(str){
  return str.split('.').reduce((r,c,i)=>i?r[c]:window[c], '');
}
console.log(getvalue(user));

Upvotes: 1

N.Tasikj
N.Tasikj

Reputation: 386

You can do it like this:

let userSplitted = "req.user.role".split('.');
let obj, o = obj = {};

userSplitted.forEach(key=>{o=o[key]={}});

Upvotes: -2

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