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Ruby rescue vs try vs ternary

All of us have faced this situation when, the current_resource object provided by devise turns out to be nil. All method invocations on current_resource on current_resource will throw an undefined method for nil:NilClass exception.

To handle this, we can try one of the following.

1. current_resource.name rescue nil
2. current_resource.try(:name)
3. current_resource ? current_resource.name : nil

But, what is the most efficient way? Let's find out.

require 'benchmark'

n = 5000000
current_resource = nil

Benchmark.bm do |x|
  x.report("rescue") do n.times { current_resource.name rescue nil } end
  x.report("try") do n.times { current_resource.try(:name) } end
  x.report("ternary") do n.times { current_resource ? current_resource.name : nil } end
end


user       system        total         real
--------------------------------------------------------------
rescue   | 16.300000   | 0.600000  | 16.900000 | (16.910213)
try      | 0.7800000   | 0.000000  | 0.7800000 | ( 0.783828)
ternary  | 0.2800000   | 0.000000  | 0.2800000 | ( 0.277966)

Note that rescue is considerably inefficient compared to the other two (almost 60 times). The Ternary operator seems to be the most sound option.

Refrences: nithinkrishna.github.io

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