Module: Async::Enumerable::Methods::Predicates::FindIndex

Defined in:
lib/async/enumerable/methods/predicates/find_index.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object 



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# File 'lib/async/enumerable/methods/predicates/find_index.rb', line 8

def self.included(base)
  base.include(::Enumerable) # Dependency
  base.include(Configurable) # Dependency for collection resolution
  base.include(ConcurrencyBounder) # Dependency
end

Instance Method Details

#find_index(value = (no_value = true), &block) ⇒ Integer?

Note:

Returns the index of the fastest completing match, not necessarily the first by position. Due to parallel execution, whichever element completes evaluation first will have its index returned. Use synchronous find_index if positional order matters.

Returns index of first matching element (parallel, early termination).

Parameters:

  • value (Object) (defaults to: (no_value = true)) —

    Value to find or omit for block form

Returns:

  • (Integer, nil) —

    Index of first match or nil



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# File 'lib/async/enumerable/methods/predicates/find_index.rb', line 20

def find_index(value = (no_value = true), &block)
  if no_value && !block_given?
    return enum_for(__method__)
  end

  result_index = Concurrent::AtomicReference.new(nil)

  __async_enumerable_bounded_concurrency(early_termination: true) do |barrier|
    __async_enumerable_collection.each_with_index do |item, index|
      break unless result_index.get.nil?

      barrier.async do
        match = no_value ? block.call(item) : (item == value)
        if match
          # Use compare_and_set to ensure only the first match wins
          if result_index.compare_and_set(nil, index)
            # Stop the barrier early when we find a match
            barrier.stop
          end
        end
      end
    end
  end

  result_index.get
end