guard<R> method
R?
guard<R>(
- R cb(
- T value
Transform an object if that value is not null.
Doing:
Map? json;
var result = json?['key']?.guard((json) => Model.fromJson(json));
is equivalent to doing:
Map? json;
var key = json?['key'];
var result = key == null ? null : Model.fromJson(key);
Implementation
R? guard<R>(R Function(T value) cb) {
if (this is T) return cb(this as T);
return null;
}