Creates an object from x with keys k if f(x[k]) returns true. If x is not a plain object, or there's no passed props, returns undefined.
x
k
f(x[k])
true
undefined
Creates an object from
x
with keysk
iff(x[k])
returnstrue
. Ifx
is not a plain object, or there's no passed props, returnsundefined
.