pipe does not properly support rest parameters in some cases.

I encountered this while updating Angular CLI.

In particular, the update to the base.ts file in there, where I'm adding as any was necessary because the spreading of an array of operators into pipe was not working.

EDIT: It seems that we can't support rest params without breaking inference enforcement from operator to operator in the pipe. So here's a proposal:

Proposed Feature

Add an overload of pipe that accepts OperatorFunction<any, any>[] and returns Observable<R>:

pipe<R>(operations: OperationFunction<any, any>[]): Observable<R>;

// usage

const operations = [map(x => x + x), filter(x => x < 100), mergeMap(n => timer(n))];

of(42).pipe(operations)