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Feature #16374

Updated by sawa (Tsuyoshi Sawada) 11 months ago

How about adding a new method to `Object` Object class? 

 ```ruby ``` 
 class Object 
	 def nullify &block 
		 block.call(self) ? nil : self 
	 end 
 end 

 irb(main):139:0> 'asdf'.nullify(&:empty?) #=> 
 => "asdf" 
 irb(main):140:0> ''.nullify(&:empty?) #=> 
 => nil 

 ``` 

 It can be used together for chaining several methods with conditions. E.g. with `&.` &. operator and `#then`: #then: 

 ```ruby ``` 
 irb(main):154:0> [1, 2].nullify(&:empty?)&.then(&:join) #=> 
 => "12" 
 irb(main):155:0> [].nullify(&:empty?)&.then(&:join) #=> 
 => nil 
 irb(main):156:0> [].join #=> 
 => "" 
 irb(main):161:0> 'a b'.nullify(&:empty?)&.then(&:split) #=> 
 => ["a", "b"] 
 irb(main):162:0> ''.nullify(&:empty?)&.then(&:split) #=> 
 => nil 
 irb(main):163:0> ''.split #=> 
 => [] 

 ``` 

 P.S. A similar opposite operation is available as a chain of [`then.detect`](https://ruby-doc.org/core-2.6.5/Object.html#method-i-then) ['then.detect'](https://ruby-doc.org/core-2.6.5/Object.html#method-i-then)

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