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Ruby Keyword Arguments - mandatory params

If you do not set a default value for a keyword argument it will become mandatory and will raise an ArgumentError.

an example:

def mandatory_keyword(bar:)
  "foo=#{bar}"
end

def default_keyword(bar: nil)
  "foo=#{bar}"
end

and its test:

describe 'keyword_arguments' do
  it { expect{mandatory_keyword()}.to raise_error(ArgumentError) }
  it { expect(mandatory_keyword(bar: 'bar')).to eq('foo=bar') }

  it { expect(default_keyword()).to eq('foo=') }
  it { expect(default_keyword(bar: 'bar')).to eq('foo=bar') }
end

In case you don’t want this behavior you can always set a default to nil.

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