Use blank? and present? in Rails

Instead of…

…using a combination of nil?, empty?, and other checks:

def process_data(input)
  if input.nil? || input.empty? || input.strip == ""
    puts "No valid input provided"
  else
    puts "Processing: #{input}"
  end
end

Use…

…Rails’s blank? and present? methods:

def process_data(input)
  if input.blank?
    puts "No valid input provided"
  else
    puts "Processing: #{input}"
  end
end

# Or, using present?
def process_data(input)
  if input.present?
    puts "Processing: #{input}"
  else
    puts "No valid input provided"
  end
end

Why?

The blank? and present? methods consolidate multiple checks into a single, readable method call. Your code becomes more expressive and easier to understand at a glance.

These methods are part of Active Support’s Core Extensions and thus work consistently across different types of objects (strings, arrays, hashes, etc.). They correctly handle cases such as strings containing only whitespace, which a simple empty? check would incorrectly classify as having meaningful content.

Here’s a quick rundown of how blank? behaves with different inputs:

nil.blank?      # => true
false.blank?    # => true
true.blank?     # => false
"".blank?       # => true
"   ".blank?    # => true
"hello".blank?  # => false
[].blank?       # => true
{}.blank?       # => true
1.blank?        # => false
0.blank?        # => false

And present? is simply the opposite of blank?:

value.present? # is equivalent to !value.blank?

Why not?

While blank? and present? are incredibly useful, there are a few situations where you might choose not to use them.

If you’re working in a pure Ruby environment, you’d need to add the active_support gem to use these methods. Or if you need to distinguish between different types of “empty” (e.g., nil vs. empty string), more specific checks might be necessary.

For extremely performance-critical code, using blank? might be slightly slower than a direct nil? or empty? check, as it can use multiple methods internally. But your mileage may vary and you should benchmark to determine if this is a concern for your specific usage.

Additional reading

For the vast majority of Rails applications, using blank? and present? leads to cleaner, more idiomatic, and more maintainable code. For a further enhancement, check out presence, which can also make your code more expressive.