Zoneawarepromise get value

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The query zoneawarepromise.getvalue is used to retrieve the resolved value of a promise that is wrapped with a zone. A zone is an execution context that persists across async tasks, such as promises and event callbacks.

To understand how zoneawarepromise.getvalue works, let’s consider an example. Assume we have a promise that resolves with a value after a certain delay using setTimeout: 

    
      const myPromise = new Promise((resolve, reject) => {
        setTimeout(() => {
          resolve('Resolved value');
        }, 2000);
      });

Now, let’s create a zone and wrap our promise with it: 

    
      const myZone = Zone.current.fork({
        name: 'My Zone',
        onInvokeTask: (parentZoneDelegate, currentZone, targetZone, task) => {
          console.log('Task invoked');
          parentZoneDelegate.invokeTask(targetZone, task);
        }
      });

      const myPromiseInZone = myZone.run(() => {
        return Promise.resolve(myPromise);
      });

In the above example, we create a new zone called “My Zone” and override the onInvokeTask method to log a message whenever a task is invoked within the zone. Then, we use the myZone.run method to execute the promise inside our zone and obtain a zone-aware promise.

To retrieve the resolved value of our zone-aware promise, we can use the zoneawarepromise.getvalue method: 

    
      const resolvedValue = zoneawarepromise.getvalue(myPromiseInZone);
      console.log(resolvedValue);
      // Output: Resolved value

The zoneawarepromise.getvalue method takes the zone-aware promise as an argument and returns the resolved value of the promise. In the example above, the resolvedValue variable will contain the string ‘Resolved value’ logged to the console.

It’s important to note that the zoneawarepromise.getvalue method should only be used when the underlying promise is known to have been resolved. If the promise is still pending, calling zoneawarepromise.getvalue will throw an error.

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