Returns TRUE for any R object that can be used as a Filter for Loggers or, Appenders:

• a function with the single argument event;

• an EventFilter R6::R6 object; or

• any object with a \$filter(event) method.

Note: A Filter must return a scalar TRUE or FALSE, but this property cannot be checked by is_filter().

is_filter(x)

## Arguments

x any R Object

## Value

TRUE or FALSE