keyStream method

ValueStream<V?> keyStream(
  1. 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";
      }
    }));