Save Navigation Operator

Just take a note from resources on internet!

1. ActiveRecord

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account = Account.new(owner: nil) # account without an owner

account.owner.address
# => NoMethodError: undefined method `address' for nil:NilClass

account && account.owner && account.owner.address
# => nil

account.try(:owner).try(:address)
# => nil

account&.owner&.address
# => nil
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account = Account.new(owner: false)

account.owner.address
# => NoMethodError: undefined method `address' for false:FalseClass `

account && account.owner && account.owner.address
# => false

account.try(:owner).try(:address)
# => nil

account&.owner&.address
# => undefined method `address' for false:FalseClass`
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account = Account.new(owner: Object.new)
# owner have not addreess column

account.owner.address
# => NoMethodError: undefined method `address' for #<Object:0x00559996b5bde8>

account && account.owner && account.owner.address
# => NoMethodError: undefined method `address' for #<Object:0x00559996b5bde8>`

account.try(:owner).try(:address)
# => nil

account&.owner&.address
# => NoMethodError: undefined method `address' for #<Object:0x00559996b5bde8>`

Catch exception with try!

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account.try!(:owner).try!(:address)
# => NoMethodError: undefined method `address' for #<Object:0x00559996b5bde8>`

2. Hash

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h = {
  key_1: {
    key_2: {
      key_3: "Value"
    }
  }
}
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h&.[](:key_1)&.[](:key_2)&.[](:key_3)
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h.dig(:key_1, :key_2, :key_3)

Resources

[1]http://mitrev.net/ruby/2015/11/13/the-operator-in-ruby/

[2]https://stackoverflow.com/questions/35922774/safe-navigation-equivalent-to-rails-try-for-hashes