Rx.Observer.prototype.checked()
Checks access to the observer for grammar violations. This includes checking for multiple onError
or onCompleted
calls, as well as reentrancy in any of the observer methods.
If a violation is detected, an Error is thrown from the offending observer method call.
返回值
(Observer): An observer that checks callbacks invocations against the observer grammar and, if the checks pass, forwards those to the specified observer.
Example
var observer = Rx.Observer.create(
x => console.log(`onNext: ${x}`),
e => console.log(`onError: ${e}`),
() => console.log('onCompleted'));
var checked = observer.checked();
checked.onNext(42);
// => onNext: 42
checked.onCompleted();
// => onCompleted
// Throws Error('Observer completed')
checked.onNext(42);