Add to_array filter

lib/liquid/condition.rb

@@ -143,24 +143,8 @@ def call_method_literal(literal, value)
       end
     end
 
-    # Implement blank? semantics matching ActiveSupport
-    # blank? returns true for nil, false, empty strings, whitespace-only strings,
-    # empty arrays, and empty hashes
     def liquid_blank?(value)
-      case value
-      when NilClass, FalseClass
-        true
-      when TrueClass, Numeric
-        false
-      when String
-        # Blank if empty or whitespace only (matches ActiveSupport)
-        value.empty? || value.match?(/\A\s*\z/)
-      when Array, Hash
-        value.empty?
-      else
-        # Fall back to empty? if available, otherwise false
-        value.respond_to?(:empty?) ? value.empty? : false
-      end
+      Liquid::Utils.blank?(value)
     end
 
     # Implement empty? semantics

lib/liquid/standardfilters.rb

@@ -315,6 +315,23 @@ def squish(input)
       Utils.to_s(input).strip.gsub(/\s+/, ' ')
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category array
+    # @liquid_summary
+    #   Converts a value into an array. Arrays are returned unchanged, blank values (`nil`, `false`,
+    #   empty or whitespace-only strings, and empty arrays) become an empty array, and any other
+    #   scalar value is wrapped in a single-element array.
+    # @liquid_syntax variable | to_array
+    # @liquid_return [array[untyped]]
+    def to_array(input)
+      return input if input.is_a?(Array)
+      return [] if Utils.blank?(input)
+      return [input] if input.is_a?(String) || input.is_a?(Numeric) || input.is_a?(TrueClass) || input.respond_to?(:strftime)
+
+      raise Liquid::ArgumentError, "cannot convert object into array"
+    end
+
     # @liquid_public_docs
     # @liquid_type filter
     # @liquid_category string

lib/liquid/utils.rb

@@ -85,6 +85,24 @@ def self.to_date(obj)
       nil
     end
 
+    # Implement blank? semantics matching ActiveSupport
+    # blank? returns true for nil, false, empty strings, whitespace-only strings,
+    # empty arrays, and empty hashes
+    def self.blank?(value)
+      case value
+      when NilClass, FalseClass
+        true
+      when TrueClass, Numeric
+        false
+      when String
+        value.empty? || value.match?(/\A\s*\z/)
+      when Array, Hash
+        value.empty?
+      else
+        value.respond_to?(:empty?) ? value.empty? : false
+      end
+    end
+
     def self.to_liquid_value(obj)
       # Enable "obj" to represent itself as a primitive value like integer, string, or boolean
       return obj.to_liquid_value if obj.respond_to?(:to_liquid_value)

test/integration/standard_filter_test.rb

@@ -171,6 +171,26 @@ def test_squish_filter
     assert_equal("", Liquid::Template.parse('{{ " " | squish }}').render)
   end
 
+  def test_to_array
+    assert_equal(['abc'], @filters.to_array('abc'))
+    assert_equal([1], @filters.to_array(1))
+    assert_equal([1, 2, 3], @filters.to_array([1, 2, 3]))
+    assert_equal([true], @filters.to_array(true))
+  end
+
+  def test_to_array_with_blank_values
+    assert_equal([], @filters.to_array(nil))
+    assert_equal([], @filters.to_array(false))
+    assert_equal([], @filters.to_array(''))
+    assert_equal([], @filters.to_array('   '))
+    assert_equal([], @filters.to_array([]))
+  end
+
+  def test_to_array_with_object_raises
+    assert_raises(Liquid::ArgumentError) { @filters.to_array({ 'a' => 1 }) }
+    assert_raises(Liquid::ArgumentError) { @filters.to_array(TestDrop.new(value: 'x')) }
+  end
+
   def test_escape
     assert_equal('&lt;strong&gt;', @filters.escape('<strong>'))
     assert_equal('1', @filters.escape(1))