isAbsent property
bool
isAbsent
Allows the distinction between the actual value null
and the value not
being available
Usually, it doesn't matter, but for rare cases, it does this method can be
used to check if a Map contains null
for a key or the key being absent
Not available could mean:
- Accessing a key which doesn't exist in a Map
- Reading the value from List when the index is greater than the length
- Trying to access a key in a Map but the found data structure is a List
pick({"a": null}, "a").isAbsent; // false
pick({"a": null}, "b").isAbsent; // true
pick([null], 0).isAbsent; // false
pick([], 2).isAbsent; // true
pick([], "a").isAbsent; // true
Implementation
bool get isAbsent => missingValueAtIndex != null;