Rx.Observable.prototype.defaultIfEmpty([defaultValue])

Returns the elements of the specified sequence or the specified value in a singleton sequence if the sequence is empty.

参数

1. [defaultValue=null] (Any): The value to return if the sequence is empty. If not provided, this defaults to null.

返回值

(Observable): An observable sequence that contains the specified default value if the source is empty; otherwise, the elements of the source itself.

例

Without a default value

With a defaultValue