Ruby/rails / chaining methods-CodePudding

Given the following example :

apply_filter_a(
 apply_filter_b(
  apply_filter_c(
    active_record_dataset
  )
 )
)

...

def apply_filter_a(records)
  # some more complex than 
  ...
end

def apply_filter_b(records)
  # some other complex logic filtering the active record dataset
  ...
end

def apply_filter_c(records)
  # some other complex logic filtering the active record dataset
  ...
end

How to simplify the nested method syntax (apply_filter_a(apply_filter_b(...)) in a more simple way ? is it possible to apply methods from an array of methods ?

CodePudding user response：

You can do this sort of folding operation with Enumerable#inject.

First, we need an array of methods. We can get those using method.

my_filters = [method(:apply_filter_c), method(:apply_filter_b), method(:apply_filter_a)]

Then we can use inject on the list of filters to apply to an initial value.

my_filters.inject(active_record_dataset) { |acc, f| f.call acc }

CodePudding user response：

There is the yield_self, or you can use its alias then. You can pipe calls one by one, each of your filter methods must return an active record relation.

apply_filter_a(active_record_dataset)
  .then { |records| apply_filter_b(records) }
  .then { |records| apply_filter_c(records) }