The logical && operator returns the left side iff it is evaluated as 'falsy'.

null && 10 
> null
0 && 10  
> 0
1 && 10 
> 10 

The nullish coalescing operator (??) returns the left side iff it is not null or undefined.

null ?? 10
> 10
0 ?? 10
> 0
1 ?? 10
> 1

Is there any neat expression to return the left side iff it is null or undefined? Basically, this would be && only for null or undefined and would look like this:

null xx 10
> null
0 xx 10
> 10
1 xx 10
> 10

I need to do the following quite often when parsing default values and it becomes a little tedious to read when someVar gets chained and parse contains more than one function.

defaults?.someVar != null ? parse(defaults.someVar) : null