Add JSON formatter

lib/erb_lint/reporters/json_reporter.rb

@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+
+require "json"
+
+module ERBLint
+  module Reporters
+    class JsonReporter < Reporter
+      def preview; end
+
+      def show
+        puts formatted_data
+      end
+
+      private
+
+      def formatted_data
+        {
+          metadata: metadata,
+          files: formatted_files,
+          summary: summary,
+        }.to_json
+      end
+
+      def metadata
+        {
+          erb_lint_version: ERBLint::VERSION,
+          ruby_engine: RUBY_ENGINE,
+          ruby_version: RUBY_VERSION,
+          ruby_patchlevel: RUBY_PATCHLEVEL.to_s,
+          ruby_platform: RUBY_PLATFORM,
+        }
+      end
+
+      def summary
+        {
+          offenses: stats.found,
+          inspected_files: stats.processed_files.size,
+          corrected: stats.corrected,
+        }
+      end
+
+      def formatted_files
+        processed_files.map do |filename, offenses|
+          {
+            path: filename,
+            offenses: formatted_offenses(offenses),
+          }
+        end
+      end
+
+      def formatted_offenses(offenses)
+        offenses.map do |offense|
+          format_offense(offense)
+        end
+      end
+
+      def format_offense(offense)
+        {
+          linter: offense.linter.class.simple_name,
+          message: offense.message.to_s,
+          location: {
+            start_line: offense.line_number,
+            start_column: offense.column,
+            last_line: offense.source_range.last_line,
+            last_column: offense.source_range.last_column,
+            length: offense.source_range.length,
+          },
+        }
+      end
+    end
+  end
+end

spec/erb_lint/cli_spec.rb

@@ -76,7 +76,7 @@ def run(_processed_source)
 
       it 'shows format instructions' do
         expect { subject }.to(
-          output(/Report offenses in the given format: \(compact, multiline\) \(default: multiline\)/).to_stdout
+          output(/Report offenses in the given format: \(compact, json, multiline\) \(default: multiline\)/).to_stdout
         )
       end
 
@@ -319,6 +319,7 @@ def run(_processed_source)
               expect { subject }.to(output(Regexp.new(Regexp.escape(<<~EOF.strip))).to_stderr)
                 nonexistentformat: is not a valid format. Available formats:
                   - compact
+                  - json
                   - multiline
               EOF
             end

spec/erb_lint/reporters/json_reporter_spec.rb

@@ -0,0 +1,98 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe ERBLint::Reporters::JsonReporter do
+  describe '.show' do
+    subject { described_class.new(stats, false).show }
+
+    let(:stats) do
+      ERBLint::Stats.new(
+        found: 2,
+        processed_files: {
+          'app/views/subscriptions/_loader.html.erb' => offenses,
+        },
+        corrected: 1
+      )
+    end
+
+    let(:offenses) do
+      [
+        instance_double(
+          ERBLint::Offense,
+          message: 'Extra space detected where there should be no space.',
+          line_number: 1,
+          column: 7,
+          source_range: instance_double(
+            BetterHtml::Tokenizer::Location,
+            last_line: 1,
+            last_column: 9,
+            length: 2,
+          ),
+          linter: ERBLint::Linters::SpaceInHtmlTag.new(nil, ERBLint::LinterConfig.new),
+        ),
+        instance_double(
+          ERBLint::Offense,
+          message: 'Remove newline before `%>` to match start of tag.',
+          line_number: 52,
+          column: 10,
+          source_range: instance_double(
+            BetterHtml::Tokenizer::Location,
+            last_line: 54,
+            last_column: 10,
+            length: 10,
+          ),
+          linter: ERBLint::Linters::ClosingErbTagIndent.new(nil, ERBLint::LinterConfig.new),
+        ),
+      ]
+    end
+
+    let(:expected_hash) do
+      {
+        metadata: {
+          erb_lint_version: ERBLint::VERSION,
+          ruby_engine: RUBY_ENGINE,
+          ruby_version: RUBY_VERSION,
+          ruby_patchlevel: RUBY_PATCHLEVEL.to_s,
+          ruby_platform: RUBY_PLATFORM,
+        },
+        files: [{
+          path: 'app/views/subscriptions/_loader.html.erb',
+          offenses: [
+            {
+              linter: 'SpaceInHtmlTag',
+              message: 'Extra space detected where there should be no space.',
+              location: {
+                start_line: 1,
+                start_column: 7,
+                last_line: 1,
+                last_column: 9,
+                length: 2,
+              },
+            },
+            {
+              linter: 'ClosingErbTagIndent',
+              message: 'Remove newline before `%>` to match start of tag.',
+              location: {
+                start_line: 52,
+                start_column: 10,
+                last_line: 54,
+                last_column: 10,
+                length: 10,
+              },
+            },
+          ],
+        }],
+        summary: {
+          offenses: 2,
+          inspected_files: 1,
+          corrected: 1,
+        },
+      }
+    end
+
+    it 'displays formatted offenses output' do
+      expect { subject }.to(output(expected_hash.to_json + "\n").to_stdout)
+    end
+  end
+end