Add as_array utility to cleanup code.

Author: gkellogg

lib/json/ld/api.rb

@@ -293,8 +293,7 @@ def self.flatten(input, context, expanded: false, **options)
 
         if context && !flattened.empty?
           # Otherwise, return the result of compacting flattened according the Compaction algorithm passing context ensuring that the compaction result uses the @graph keyword (or its alias) at the top-level, even if the context is empty or if there is only one element to put in the @graph array. This ensures that the returned document has a deterministic structure.
-          compacted = compact(flattened)
-          compacted = [compacted] unless compacted.is_a?(Array)
+          compacted = as_array(compact(flattened))
           kwgraph = self.context.compact_iri('@graph', quiet: true)
           flattened = self.context.serialize.merge(kwgraph => compacted)
         end

lib/json/ld/compact.rb

@@ -172,7 +172,7 @@ def compact(element, property: nil)
 
             # handle @list
             if list?(expanded_item)
-              compacted_item = [compacted_item] unless compacted_item.is_a?(Array)
+              compacted_item = as_array(compacted_item)
               unless container == %w(@list)
                 al = context.compact_iri('@list', vocab: true, quiet: true)
                 compacted_item = {al => compacted_item}

lib/json/ld/context.rb

@@ -385,7 +385,7 @@ def parse(local_context, remote_contexts = [])
       result = self.dup
       result.provided_context = local_context if self.empty?
 
-      local_context = [local_context] unless local_context.is_a?(Array)
+      local_context = as_array(local_context)
 
       local_context.each do |context|
         case context

lib/json/ld/expand.rb

@@ -196,8 +196,8 @@ def expand_object(input, active_property, context, output_object, ordered:, fram
             end
 
             # Use array form if framing
-            if framing && !e_id.is_a?(Array)
-              [e_id]
+            if framing
+              as_array(e_id)
             else
               e_id
             end
@@ -226,7 +226,7 @@ def expand_object(input, active_property, context, output_object, ordered:, fram
           when '@graph'
             # If expanded property is @graph, set expanded value to the result of using this algorithm recursively passing active context, @graph for active property, and value for element.
             value = expand(value, '@graph', context, ordered: ordered, framing: framing)
-            value.is_a?(Array) ? value : [value]
+            as_array(value)
           when '@value'
             # If expanded property is @value and value is not a scalar or null, an invalid value object value error has been detected and processing is aborted. Otherwise, set expanded value to value. If expanded value is null, set the @value member of result to null and continue with the next key from element. Null values need to be preserved in this case as the meaning of an @type member depends on the existence of an @value member.
             # If framing, always use array form, unless null
@@ -281,7 +281,7 @@ def expand_object(input, active_property, context, output_object, ordered:, fram
             value = expand(value, active_property, context, ordered: ordered, framing: framing)
 
             # Spec FIXME: need to be sure that result is an array
-            value = [value] unless value.is_a?(Array)
+            value = as_array(value)
 
             # If expanded value is a list object, a list of lists error has been detected and processing is aborted.
             # Spec FIXME: Also look at each object if result is an array
@@ -399,15 +399,13 @@ def expand_object(input, active_property, context, output_object, ordered:, fram
               when %w(@graph @index), %w(@index)
                 # Indexed graph by graph name
                 if !graph?(item) && container.include?('@graph')
-                  item = [item] unless expanded_value.is_a?(Array)
-                  item = {'@graph' => item}
+                  item = {'@graph' => as_array(item)}
                 end
                 item['@index'] ||= k unless expanded_k == '@none'
               when %w(@graph @id), %w(@id)
                 # Indexed graph by graph name
                 if !graph?(item) && container.include?('@graph')
-                  item = [item] unless expanded_value.is_a?(Array)
-                  item = {'@graph' => item}
+                  item = {'@graph' => as_array(item)}
                 end
                 # Expand k document relative
                 expanded_k = active_context.expand_iri(k, documentRelative: true, quiet: true).to_s unless expanded_k == '@none'
@@ -436,8 +434,7 @@ def expand_object(input, active_property, context, output_object, ordered:, fram
         # If the container mapping associated to key in active context is @list and expanded value is not already a list object, convert expanded value to a list object by first setting it to an array containing only expanded value if it is not already an array, and then by setting it to a JSON object containing the key-value pair @list-expanded value.
         if active_context.container(key) == %w(@list) && !list?(expanded_value)
           #log_debug(" => ") { "convert #{expanded_value.inspect} to list"}
-          expanded_value = [expanded_value] unless expanded_value.is_a?(Array)
-          expanded_value = {'@list' => expanded_value}
+          expanded_value = {'@list' => as_array(expanded_value)}
         end
         #log_debug {" => #{expanded_value.inspect}"}
 
@@ -472,8 +469,7 @@ def expand_object(input, active_property, context, output_object, ordered:, fram
 
       # For each key in nests, recusively expand content
       nests.each do |key|
-        nested_values = input[key]
-        nested_values = [input[key]] unless input[key].is_a?(Array)
+        nested_values = as_array(input[key])
         nested_values.each do |nv|
           raise JsonLdError::InvalidNestValue, nv.inspect unless
             nv.is_a?(Hash) && nv.keys.none? {|k| context.expand_iri(k, vocab: true) == '@value'}

lib/json/ld/frame.rb

@@ -160,8 +160,7 @@ def frame(state, subjects, frame, parent: nil, property: nil, **options)
           n = frame[prop].first || {}
           omit_default_on = get_frame_flag(n, options, :omitDefault)
           if !omit_default_on && !output[prop]
-            preserve = n.fetch('@default', '@null').dup
-            preserve = [preserve] unless preserve.is_a?(Array)
+            preserve = as_array(n.fetch('@default', '@null').dup)
             output[prop] = [{'@preserve' => preserve}]
           end
         end

lib/json/ld/utils.rb

@@ -110,6 +110,14 @@ def as_resource(id, base = nil)
       end
     end
 
+    ##
+    # Represent as an array
+    # @param [Object] object
+    # @return [Array<Object>]
+    def as_array(object)
+      object.is_a?(Array) ? object : [object]
+    end
+
     ##
     # Compares two JSON-LD values for equality. Two JSON-LD values will be
     # considered equal if: