Rxjs documentation for 'find' operator is wrong

[cmaart]

The documentation at http://reactivex.io/documentation/operators/first.html is slightly wrong for the find operator, in rxjs at least. Documentation says that find emits undefined when no element matches. This is not correct, actually it just completes the observable. The sample given:

var array = [1,2,3,4];

var source = Rx.Observable.fromArray(array)
    .find(function (x, i, obs) {
        return x === 5;
    });

var subscription = source.subscribe(
    function (x) { console.log('Next: ' + x); },
    function (err) { console.log('Error: ' + err); },
    function () { console.log('Completed'); });

outputs accordin to the documentation:

Next: undefined
Completed

but actually outputs: Completed

Also see rxjs documentation for find: https://github.com/Reactive-Extensions/RxJS/blob/master/doc/api/core/operators/find.md

[akarnokd]

According to the most recent official docs, it is supposed to emit undefined:

https://rxjs.dev/api/index/function/find