keyStream method
ValueStream<V?>
keyStream(
- K key
Allows for observation of a single map key.
Implementation
ValueStream<V?> keyStream(K key) => HStream<V?>(
this[key],
changeStream.expand((changes) => changes).where((change) => change.key == key).map((change) {
switch (change.type) {
case MapDiffType.unset:
return null;
case MapDiffType.change:
return change.value;
case MapDiffType.set:
return change.value;
default:
throw "Invalid type - must be a known MapDiff type";
}
}));