New grouped_checkbox method for use with Array attributes

spec/lucky/ext/input_helpers_spec.cr

@@ -54,6 +54,17 @@ class InputTestForm
   end
 end
 
+class ComplexInputTestForm
+  def names(value : Array(String))
+    Avram::PermittedAttribute(Array(String)).new(
+      name: :names,
+      param: nil,
+      value: value,
+      param_key: "bucket"
+    )
+  end
+end
+
 private class TestPage
   include Lucky::HTMLPage
 
@@ -106,6 +117,21 @@ describe Lucky::InputHelpers do
     end
   end
 
+  describe "grouped checkboxes" do
+    it "renders the grouped checkboxes" do
+      array_field = complex_form.names(["Green", "Sky Blue", "Gold"])
+      view(&.grouped_checkbox(array_field, "WiggleBrown")).should contain <<-HTML
+      <input type="checkbox" id="bucket_names_0" name="bucket:names[]" value="WiggleBrown">
+      HTML
+      view(&.grouped_checkbox(array_field, "Sky Blue")).should contain <<-HTML
+      <input type="checkbox" id="bucket_names_0" name="bucket:names[]" value="Sky Blue" checked>
+      HTML
+      view(&.grouped_checkbox(array_field, "Sky Blue", attrs: [:required], class: "inline")).should contain <<-HTML
+      <input type="checkbox" id="bucket_names_0" name="bucket:names[]" value="Sky Blue" class="inline" required checked>
+      HTML
+    end
+  end
+
   describe "radio inputs" do
     it "renders radio inputs" do
       radio_field = form.status("approved")
@@ -325,6 +351,10 @@ private def form
   InputTestForm.new
 end
 
+private def complex_form
+  ComplexInputTestForm.new
+end
+
 private def array_attribute
   Avram::PermittedAttribute.new(name: :group, param: nil, value: ["one", "two"], param_key: "key")
 end

src/lucky/ext/input_helpers.cr

@@ -86,6 +86,21 @@ module Lucky::InputHelpers
 
   generate_helpful_error_for checkbox
 
+  def grouped_checkbox(
+    field : Avram::PermittedAttribute(Array),
+    checked_value : String,
+    attrs : Array(Symbol) = [] of Symbol,
+    **html_options
+  ) : Nil
+    if field.value.try(&.includes?(checked_value))
+      attrs = attrs | [:checked]
+    end
+    html_options = merge_options(html_options, {"value" => checked_value})
+    generate_input(field, "checkbox", html_options, attrs: attrs)
+  end
+
+  generate_helpful_error_for grouped_checkbox
+
   # Returns a radio input field.
   #
   # ```