Added smart_trim method for better logging

lib/react_on_rails/prerender_error.rb

@@ -59,9 +59,12 @@ def calc_message(component_name, console_messages, err, js_code, props)
       end
       # rubocop:disable Layout/IndentHeredoc
       message << <<-MSG
-when prerendering #{component_name} with props (truncated): #{props.to_s[0, MAX_ERROR_SNIPPET_TO_LOG]}
-js_code was:
-#{js_code[0, MAX_ERROR_SNIPPET_TO_LOG]}
+when prerendering #{component_name} with props: #{Utils.smart_trim(props, MAX_ERROR_SNIPPET_TO_LOG)}
+
+code:
+
+#{Utils.smart_trim(js_code, MAX_ERROR_SNIPPET_TO_LOG)}
+
       MSG
       # rubocop:enable Layout/IndentHeredoc
 

lib/react_on_rails/utils.rb

@@ -8,6 +8,8 @@
 
 module ReactOnRails
   module Utils
+    TRUNCATION_FILLER = "\n... TRUNCATED ...\n"
+
     # https://forum.shakacode.com/t/yak-of-the-week-ruby-2-4-pathname-empty-changed-to-look-at-file-size/901
     # return object if truthy, else return nil
     def self.truthy_presence(obj)
@@ -152,5 +154,20 @@ def self.gem_available?(name)
     def self.react_on_rails_pro?
       @react_on_rails_pro ||= gem_available?("react_on_rails_pro")
     end
+
+    def self.smart_trim(str, max_length = 1000)
+      # From https://stackoverflow.com/a/831583/1009332
+      str = str.to_s
+      return str unless str.present? && max_length >= 1
+      return str if str.length <= max_length
+
+      return str[0, 1] + TRUNCATION_FILLER if max_length == 1
+
+      midpoint = (str.length / 2.0).ceil;
+      to_remove = str.length - max_length;
+      lstrip = (to_remove / 2.0).ceil;
+      rstrip = to_remove - lstrip;
+      str[0..(midpoint - lstrip - 1)] + TRUNCATION_FILLER + str[(midpoint + rstrip)..-1]
+    end
   end
 end

spec/react_on_rails/utils_spec.rb

@@ -25,11 +25,11 @@ module ReactOnRails
         end
         before do
           allow(ReactOnRails).to receive_message_chain(:configuration, :generated_assets_dir)
-            .and_return("")
+                                   .and_return("")
           allow(Webpacker).to receive_message_chain("dev_server.running?")
-            .and_return(false)
+                                .and_return(false)
           allow(Webpacker).to receive_message_chain("config.public_output_path")
-            .and_return(webpacker_public_output_path)
+                                .and_return(webpacker_public_output_path)
           allow(ReactOnRails::WebpackerUtils).to receive(:using_webpacker?).and_return(true)
         end
 
@@ -39,8 +39,8 @@ module ReactOnRails
             # [2] (pry) ReactOnRails::WebpackerUtils: 0> Webpacker.manifest.lookup("app-bundle.js")
             # "/webpack/development/app-bundle-c1d2b6ab73dffa7d9c0e.js"
             allow(Webpacker).to receive_message_chain("manifest.lookup!")
-              .with("webpack-bundle.js")
-              .and_return("/webpack/dev/webpack-bundle-0123456789abcdef.js")
+                                  .with("webpack-bundle.js")
+                                  .and_return("/webpack/dev/webpack-bundle-0123456789abcdef.js")
           end
 
           it { expect(subject).to eq("#{webpacker_public_output_path}/webpack-bundle-0123456789abcdef.js") }
@@ -58,14 +58,14 @@ module ReactOnRails
       context "Without Webpacker enabled" do
         before do
           allow(ReactOnRails).to receive_message_chain(:configuration, :generated_assets_dir)
-            .and_return("public/webpack/dev")
+                                   .and_return("public/webpack/dev")
           allow(ReactOnRails::WebpackerUtils).to receive(:using_webpacker?).and_return(false)
         end
 
         it {
           expect(subject).to eq(File.expand_path(
-                                  File.join(Rails.root,
-                                            "public/webpack/dev/webpack-bundle.js")
+            File.join(Rails.root,
+                      "public/webpack/dev/webpack-bundle.js")
           ))
         }
       end
@@ -76,17 +76,17 @@ module ReactOnRails
         allow(Rails).to receive(:root).and_return(Pathname.new("."))
         allow(ReactOnRails::WebpackerUtils).to receive(:using_webpacker?).and_return(true)
         allow(Webpacker).to receive_message_chain("config.public_output_path")
-          .and_return(Pathname.new("public/webpack/development"))
+                              .and_return(Pathname.new("public/webpack/development"))
       end
 
       context "With Webpacker enabled and server file not in manifest", :webpacker do
         it "returns the unhashed server path" do
           server_bundle_name = "server-bundle.js"
           allow(ReactOnRails).to receive_message_chain("configuration.server_bundle_js_file")
-            .and_return(server_bundle_name)
+                                   .and_return(server_bundle_name)
           allow(Webpacker).to receive_message_chain("manifest.lookup!")
-            .with(server_bundle_name)
-            .and_raise(Webpacker::Manifest::MissingEntryError)
+                                .with(server_bundle_name)
+                                .and_raise(Webpacker::Manifest::MissingEntryError)
 
           path = Utils.server_bundle_js_file_path
 
@@ -97,10 +97,10 @@ module ReactOnRails
       context "With Webpacker enabled and server file in the manifest", :webpacker do
         it "returns the correct path hashed server path" do
           allow(ReactOnRails).to receive_message_chain("configuration.server_bundle_js_file")
-            .and_return("webpack-bundle.js")
+                                   .and_return("webpack-bundle.js")
           allow(Webpacker).to receive_message_chain("manifest.lookup!")
-            .with("webpack-bundle.js")
-            .and_return("webpack/development/webpack-bundle-123456.js")
+                                .with("webpack-bundle.js")
+                                .and_return("webpack/development/webpack-bundle-123456.js")
 
           path = Utils.server_bundle_js_file_path
 
@@ -247,6 +247,33 @@ module ReactOnRails
         end
       end
     end
+
+    describe ".smart_trim" do
+      it "trims smartly" do
+        s = '1234567890'
+
+        expect(Utils.smart_trim(s, -1)).to eq('1234567890')
+        expect(Utils.smart_trim(s, 0)).to eq('1234567890')
+        expect(Utils.smart_trim(s, 1)).to eq("1#{Utils::TRUNCATION_FILLER}")
+        expect(Utils.smart_trim(s, 2)).to eq("1#{Utils::TRUNCATION_FILLER}0")
+        expect(Utils.smart_trim(s, 3)).to eq("1#{Utils::TRUNCATION_FILLER}90")
+        expect(Utils.smart_trim(s, 4)).to eq("12#{Utils::TRUNCATION_FILLER}90")
+        expect(Utils.smart_trim(s, 5)).to eq("12#{Utils::TRUNCATION_FILLER}890")
+        expect(Utils.smart_trim(s, 6)).to eq("123#{Utils::TRUNCATION_FILLER}890")
+        expect(Utils.smart_trim(s, 7)).to eq("123#{Utils::TRUNCATION_FILLER}7890")
+        expect(Utils.smart_trim(s, 8)).to eq("1234#{Utils::TRUNCATION_FILLER}7890")
+        expect(Utils.smart_trim(s, 9)).to eq("1234#{Utils::TRUNCATION_FILLER}67890")
+        expect(Utils.smart_trim(s, 10)).to eq('1234567890')
+        expect(Utils.smart_trim(s, 11)).to eq('1234567890')
+      end
+
+      it "trims handles a hash" do
+        s = { a: '1234567890' }
+
+        expect(Utils.smart_trim(s, 9)).to eq(
+                                            "{:a=#{Utils::TRUNCATION_FILLER}890\"}")
+      end
+    end
   end
 end
 # rubocop:enable Metrics/ModuleLength, Metrics/BlockLength