Merge pull request #19 from tomfwz/strong-parameters-with-array

TIL Rails: Strong parameters with array

Author: stevenyap

rails/strong-parameters-with-array.md

@@ -0,0 +1,25 @@
+By default, strong parameter just permit parameter with values are string.
+
+```ruby
+"category"=>{"options_attributes"=>{"0"=>{"value"=>["FSE", "FDI"], "id"=>"61"}, "1"=>{"value"=>"14", "id"=>"62"}, "2"=>{"value"=>"10", "id"=>"63"}}}
+
+params.require(:category).permit(options_attributes: [:id, :value])
+
+{"options_attributes"=>{"0"=>{"id"=>"61"}, "1"=>{"id"=>"62", "value"=>"14"}, "2"=>{"id"=>"63", "value"=>"10"}}}
+```
+
+If you need to permit parameter with values are an array. Let's use:
+
+```ruby
+params.require(:category).permit(options_attributes: [:id, value: []])
+
+{"options_attributes"=>{"0"=>{"id"=>"61", "value"=>["FSE", "FDI"]}, "1"=>{"id"=>"62"}, "2"=>{"id"=>"63"}}}
+```
+
+But the string values are cleared out, so in case you need to permit both of string values and array values. Let's use simple trick:
+
+```ruby
+params.require(:category).permit(options_attributes: [:id, :value, value: []])
+
+{"options_attributes"=>{"0"=>{"id"=>"61", "value"=>["FSE", "FDI"]}, "1"=>{"id"=>"62", "value"=>"14"}, "2"=>{"id"=>"63", "value"=>"10"}}}
+```