Is there a one liner in javascript to use an array of string as an object path?

Question

let's say I have the following array :

let path = ['foo','bar']

And I have this item :

let item = {
    faa: 'whatever',
    foo: {
        bar: 'hello there', //general kenobi
        bor: 'nope'
    }
}

I want to access "hello there" using something looking like :

item[path] or item.path or item[path.join(".")]

You get the idea, is this doable and if yes, how ? (of course what is written in this question does not work)

Denys Séguret · Accepted Answer · 2018-12-20 09:50:24Z

5

You can do

let target = path.reduce((o, t)=> o ? o[t] : undefined, item)

This one-liner is designed to ensure there won't be any error if there's no match: it just returns undefined.

Demonstration:

let item = {
    faa: 'whatever',
    foo: {
        bar: 'hello there', //general kenobi
        bor: 'nope'
    }
}
let path = ['foo','bar']
let target = path.reduce((o, t)=> o ? o[t] : undefined, item)
console.log(target)

edited Dec 20, 2018 at 9:50

answered Dec 20, 2018 at 9:43

Denys Séguret

384k90 gold badges813 silver badges780 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Tom Over a year ago

Yup, just tested it myself, it does work ! Thank you good sir, accepting your answer in 10 minutes when allowed by SO

Denys Séguret Over a year ago

I use this exact pattern in one of my applications to get configuration items: github.com/Canop/miaou/blob/master/libs/Miaou.js#L34

Tom Over a year ago

This will be used for a very similar purpose !

Hadi Ranjbar · Accepted Answer · 2018-12-20 09:57:40Z

0

You can also use the third party libraries like Lodash.

then you can use Lodash get like this:

import {get} from Lodash

var x=get(item,path.join("."))

The good thing about it is if the item doesn't have 'foo', you won't get an error. It works like safe navigation on an object.

edited Dec 20, 2018 at 9:57

answered Dec 20, 2018 at 9:52

Hadi Ranjbar

1,8224 gold badges25 silver badges44 bronze badges

Collectives™ on Stack Overflow

Is there a one liner in javascript to use an array of string as an object path?

2 Answers 2

3 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related