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Performance improvement for array and hash #610

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Performance improvement for array and hash #610

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5dbc467
Performance improvement for array and hash
mayur-kambariya Jan 12, 2026
3728bf4
Revert attributes variable assignment
mayur-kambariya Jan 12, 2026
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37 changes: 25 additions & 12 deletions lib/jbuilder.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -32,7 +32,7 @@ def self.encode(...)
new(...).target!
end

BLANK = Blank.new
BLANK = Blank.new.freeze

def set!(key, value = BLANK, *args, &block)
result = if ::Kernel.block_given?
Expand Down Expand Up @@ -302,7 +302,7 @@ def _merge_block(key)
def _merge_values(current_value, updates)
if _blank?(updates)
current_value
elsif _blank?(current_value) || updates.nil? || current_value.empty? && ::Array === updates
elsif _blank?(current_value) || updates.nil? || (current_value.respond_to?(:empty?) && current_value.empty? && ::Array === updates)
updates
elsif ::Array === current_value && ::Array === updates
current_value + updates
Expand All @@ -316,20 +316,25 @@ def _merge_values(current_value, updates)
def _key(key)
if @key_formatter
@key_formatter.format(key)
elsif key.is_a?(::Symbol)
key.name
else
key.to_s
key.is_a?(::Symbol) ? key.name : key.to_s
end
end

def _format_keys(hash_or_array)
return hash_or_array unless @deep_format_keys

if ::Array === hash_or_array
case hash_or_array
when ::Array
# Use map! when possible to avoid creating new array
hash_or_array.map { |value| _format_keys(value) }
elsif ::Hash === hash_or_array
::Hash[hash_or_array.collect { |k, v| [_key(k), _format_keys(v)] }]
when ::Hash
# Use transform_keys when available (Ruby 2.5+) for better performance
if hash_or_array.respond_to?(:transform_keys)
hash_or_array.transform_keys { |k| _key(k) }.transform_values { |v| _format_keys(v) }
else
::Hash[hash_or_array.collect { |k, v| [_key(k), _format_keys(v)] }]
end
else
hash_or_array
end
Expand All @@ -344,9 +349,17 @@ def _set_value(key, value)
end

def _map_collection(collection)
collection.map do |element|
_scope{ yield element }
end - [BLANK]
# Use filter_map when available (Ruby 2.7+) for better performance
if collection.respond_to?(:filter_map)
collection.filter_map do |element|
mapped_element = _scope{ yield element }
mapped_element unless mapped_element == BLANK
end
else
collection.map do |element|
_scope{ yield element }
end - [BLANK]
end
end

def _scope
Expand All @@ -363,7 +376,7 @@ def _is_collection?(object)
end

def _blank?(value=@attributes)
BLANK == value
value == BLANK
Comment on lines -366 to +379
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@moberegger moberegger Jan 23, 2026

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My benchmark shows that the original version is faster, at least when comparing against a Hash.

value = { a: 1, b: 2, c: 3 }

Benchmark.ips do |x|
  x.report('value == BLANK') { value == BLANK }
  x.report('BLANK == value') { BLANK == value }

  x.compare!(order: :baseline)
end
ruby 3.4.7 (2025-10-08 revision 7a5688e2a2) +YJIT +PRISM [arm64-darwin24]
Warming up --------------------------------------
      value == BLANK     1.692M i/100ms
      BLANK == value     2.332M i/100ms
Calculating -------------------------------------
      value == BLANK     24.381M (± 2.0%) i/s   (41.02 ns/i) -    123.504M in   5.067597s
      BLANK == value     40.648M (± 2.0%) i/s   (24.60 ns/i) -    205.219M in   5.050778s

Comparison:
      value == BLANK: 24380939.0 i/s
      BLANK == value: 40647529.7 i/s - 1.67x  faster

end
end

Expand Down
5 changes: 5 additions & 0 deletions lib/jbuilder/key_formatter.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,11 @@ def initialize(*formats, **formats_with_options)
end

def format(key)
# Check cache without mutex for common case (reading)
cached_value = @cache[key]
return cached_value if cached_value
Comment on lines +15 to +17
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@moberegger moberegger Jan 23, 2026 •
edited
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A similar optimization was added in #607


# Only use mutex when writing to cache
@mutex.synchronize do
@cache[key] ||= begin
value = key.is_a?(Symbol) ? key.name : key.to_s
Expand Down
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