ES16 offers a nice shorthand obj.someMethod?.() to call someMethod if exists on calling object.

Beeing spoiled with this coding sugar, I would also like to assign a value to property if exists, something like obj?.someProp = 42 (which leads to invalid left-hand assignment).

I would like to do it with any object (mostly dataset of HTMLElements). Any idea how to shorten this?

if(obj?.hasOwnProperty("someProp")) obj.someProp = 42

CodePudding user response：

You can use the logical nullish assignment operator. It won't help you with obj being undefined though:

if (obj) obj.someProp ??= 42;

CodePudding user response：

well, you can do something like:

obj && (obj.someProp = 42)

But this will not create the obj for you..

However, even though its not asked, why not just simply destructure though?

obj = {...(obj || {}), someProp: 42}