2 Matching Annotations
- Mar 2021
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dry-rb.org dry-rb.org
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Dry::Types::Undefined
Cool! I workaround for the fact that Ruby has no undefined type distinct from nil.
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- Feb 2021
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github.com github.com
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There are times where it is useful to know whether a value was passed to run or the result of a filter default. In particular, it is useful when nil is an acceptable value.
Yes! An illustration in ruby:
main > h = {key_with_nil_value: nil} => {:key_with_nil_value=>nil} main > h[:key_with_nil_value] => nil main > h[:missing_key] # this would be undefined in JavaScript (a useful distinction) rather than null, but in Ruby it's indistinguishable from the case where a nil value was actually explicitly _supplied_ by the caller/user => nil # so we have to check for "missingness" ("undefinedness"?) differently in Ruby main > h.key?(:key_with_nil_value) => true main > h.key?(:missing_key) => false
This is one unfortunate side effect of Ruby having only
nil
and no built-in way to distinguish betweennull
andundefined
like in JavaScript.
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