///
module Rx {
export interface Observable {
/**
* Returns the first index at which a given element can be found in the observable sequence, or -1 if it is not present.
* @param {Any} searchElement Element to locate in the array.
* @param {Number} [fromIndex] The index to start the search. If not specified, defaults to 0.
* @returns {Observable} And observable sequence containing the first index at which a given element can be found in the observable sequence, or -1 if it is not present.
*/
indexOf(element: T, fromIndex?: number): Observable;
}
}
(function () {
var o : Rx.Observable;
var b : Rx.Observable = o.indexOf('a');
var b : Rx.Observable = o.indexOf('a', 1);
});