Function once

once<TObsv, TPath>(obj, path, options?): Promise<void>
Watches the given path on the given object for the first change.

See support/observableUtils!watch for more details.
Type Parameters
- TObsv extends Observable
- TPath extends string
Parameters
- obj: TObsv
  The object to watch.
- path: TPath
  The property path to watch.
- Optionaloptions: {
  signal?: AbortSignal;
  }
  Optional. The options to use for watching the property.
  - Optionalsignal?: AbortSignal
    Optional signal to abort. The promise will be rejected if the signal is aborted.
Returns Promise<void>
Throws
Error if the object is not observable.

Throws
Error if the path is to a non-configurable property.

Throws
Error if the path is not a valid property path.