JavaScript: Check if Object is null or undefined when getting property

Question

I wanna do like this simply:

const someProp = someObj ? someObj.someProp : undefined;

In Ruby, we can use & operator.

some_prop = some_obj&.some_prop

Possible duplicate of stackoverflow.com/questions/2647867/… — Inus Saha
– Inus Saha, Commented Jun 21, 2018 at 12:14
Possible duplicate of How to determine if variable is 'undefined' or 'null'? — The Reason
– The Reason, Commented Jun 21, 2018 at 12:16
This article should be a good read for you to understand what your options are. — mhodges
– mhodges, Commented Jun 21, 2018 at 15:40

Felix Kling · Accepted Answer · 2018-06-21 16:03:50Z

2

You are looking for the optional chaining operator which is also currently a stage 1 proposal:

const someProp = someObj?.someProp;

However, for the time being you could write a helper function:

function opt(obj, prop) {
  return obj ? obj.prop : null;
}

const someProp = opt(someObj, 'someProp');

answered Jun 21, 2018 at 16:03

Felix Kling

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Comments

Axnyff · Accepted Answer · 2018-06-21 12:22:33Z

1

There's no such operator currently in javascript.

There's a proposal for ?? to be added https://github.com/tc39/proposal-nullish-coalescing, but it's only at stage 1 meaning it's far from being in the language yet.

answered Jun 21, 2018 at 12:22

Axnyff

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