Widens a parameter to every shape a caller may have at hand: nothing (undefined), a lone value, or any
collection of values, leaving some to normalise the argument into an array.
T itself may not be an object iterable: a Set, Map, typed array, array, or generator passed as a value is
indistinguishable from a collection of values and is read as the latter. Strings are exempt and stay singular.
Zero, one, or many values of type
T.Widens a parameter to every shape a caller may have at hand: nothing (
undefined), a lone value, or any collection of values, leaving some to normalise the argument into an array.Titself may not be an object iterable: aSet,Map, typed array, array, or generator passed as a value is indistinguishable from a collection of values and is read as the latter. Strings are exempt and stay singular.