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31 lines
857 B
Markdown
31 lines
857 B
Markdown
# Reference Hash Key With Safe Navigation
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Let's say we have a variable that we expect to be a hash, but could also be
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`nil`. We want to try to grab a value from that hash by referencing a specific
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key. Because it could be `nil`, we cannot simply do:
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```ruby
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stuff[:key]
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```
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As that could result in `NoMethodError: undefined method '[]' for nil
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(NoMethodError)`.
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We should use the _safe navigation_ operator (`&`) to avoid raising that error.
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However, we should pay attention to a necessary syntax shift from the short-hand
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`[:key]` to the long-hand `[](:key)`.
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```ruby
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stuff&.[](:key)
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```
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The meaning of this syntax is that we are calling the `#[]` method and we pass
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it a single argument `:key` wrapped in parentheses.
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Another approach would be to use `#dig` which can feel more ergonomic than the
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above syntax switch.
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```ruby
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stuff&.dig(:key)
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```
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