# Methods and Operators Methods are functions attached to a Stream instance, like `stream.addListener()`. Operators are also methods, but return a new Stream, leaving the existing Stream unmodified, except for the fact that it has a child Stream attached as Listener. o.type === 'factory') === -1) { ?> ### `()` ### `` **Deprecated** See: 0) { ?> #### Arguments: - `: ` 0) { ?> #### Returns: - - -