Using an array to access (deeply) nested object properties [duplicate]

Question

Given javascript object:

obj = {
    a: {
        b: {
            c: 3
           }
       }
   }

I can access the deepest property as follows: obj['a']['b']['c'] or obj.a.b.c. Now I want to access this using an array ['a', 'b', 'c']. How can I access the same object property using this array?

Note: the method does not have to "safe", so no need to check for: typeError: cannot read property ... of undefined.

Yes, I can come up with a recursive solution but the problem seems so basic that I am afraid that I am missing something super obvious. (And I already need this as part of another recursive problem) — Roy Prins
– Roy Prins, Commented Apr 24, 2019 at 20:04

Kobe · Accepted Answer · 2019-07-04 14:39:09Z

4

You can do this using reduce method and pass your object as accumulator param.

const obj = {
  a: {
    b: {
      c: 3
    }
  }
}

const key = ['a', 'b', 'c'];

function get(obj, key) {
  return key.reduce((r, e, i, a) => {
    return r[e] || (a[i + 1] ? {} : undefined)
  }, obj)
}

console.log(get(obj, key))

edited Jul 4, 2019 at 14:39

Kobe

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answered Apr 24, 2019 at 20:06

Nenad Vracar

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2 Comments

Kobe Over a year ago

Im just trying to find away to access the object in this way but then also mutate that object, but I can't seem to get that to work.

Nenad Vracar Over a year ago

There are lots of different options based on your requirements how you want to set new value but you could start with something like this jsfiddle.net/syathrdg/3, also take a look at lodash set method.

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