class ActiveSupport::ParameterFilter

> reverses the value to all keys matching /secret/i
end])
v.reverse! if k =~ /secret/i
ActiveSupport::ParameterFilter.new([-> (k, v) do
change { file: { code: “xxxx”} }
=> replaces { credit_card: {code: “xxxx”} } with “[FILTERED]”, does not<br>ActiveSupport::ParameterFilter.new()
=> replaces the value to all keys matching /foo|bar/i with “[FILTERED]”
ActiveSupport::ParameterFilter.new([:foo, “bar”])
=> replaces the value to all keys matching /password/i with “[FILTERED]”<br>ActiveSupport::ParameterFilter.new()
using String#replace or similar methods.
all sub-hashes are passed to it, where the value or the key can be replaced
’credit_card.number’. If a proc is given, each key and value of a hash and
sub-keys from a hash is possible by using the dot notation:
hash-like object and replace corresponding value. Filtering only certain
ParameterFilter allows you to specify keys for sensitive data from ↑

def compiled_filter 

def compiled_filter
  @compiled_filter ||= CompiledFilter.compile(@filters, mask: @mask)
end

def filter(params)

Mask value of +params+ if key matches one of filters. 
def filter(params)
  compiled_filter.call(params)
end

def filter_param(key, value)

Returns filtered value for given key. For +Proc+ filters, third block argument is not populated. 
def filter_param(key, value)
  @filters.empty? ? value : compiled_filter.value_for_key(key, value)
end

def initialize(filters = [], mask: FILTERED)

* :mask - A replaced object when filtered. Defaults to +"[FILTERED]"+

==== Options

For +Proc+ filters, key, value, and optional original hash is passed to block arguments.
Other types of filters are treated as +String+ using +to_s+.
Create instance with given filters. Supported type of filters are +String+, +Regexp+, and +Proc+. 
def initialize(filters = [], mask: FILTERED)
  @filters = filters
  @mask = mask
end