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
It was raised in the tc39 proposal that brought us optional chaining under the discussion should we include "optional property assignment" a?.b = c, but ultimately not supported.
However, this is supported by CoffeeScript's existential operator which given the following example:
el?.href = "b"
CoffeeScript will compile into the following output:
if (el != null) {
el.href = "b";
}