WIP

pom.xml

@@ -58,6 +58,10 @@
       <version>1.24.8</version>
       <optional>true</optional>
     </dependency>
+    <dependency>
+      <groupId>org.jenkins-ci.plugins</groupId>
+      <artifactId>jackson2-api</artifactId>
+    </dependency>
     <dependency>
       <groupId>io.jenkins</groupId>
       <artifactId>configuration-as-code</artifactId>

src/main/java/io/jenkins/plugins/thememanager/Theme.java

@@ -3,6 +3,7 @@
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
 
+import com.fasterxml.jackson.databind.ObjectMapper;
 import java.text.MessageFormat;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -22,6 +23,11 @@
 public class Theme {
 
   private static final String JS_HTML = "<script type=\"text/javascript\" src=\"{0}\"></script>";
+  private static final String JSON_HTML =
+      "<script id=\"theme-manager-{0}\" type=\"application/json\">{1}</script>";
+
+  private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
+
   private static final String CSS_HTML =
       "<link type=\"text/css\" rel=\"stylesheet\" href=\"{0}\"/>";
 
@@ -55,6 +61,14 @@ Set<String> generateHeaderElements(boolean injectCss) {
       headerElements.add(MessageFormat.format(JS_HTML, javascriptUrl));
     }
 
+    try {
+      headerElements.add(
+          MessageFormat.format(
+              JSON_HTML, "properties", OBJECT_MAPPER.writeValueAsString(properties)));
+    } catch (Exception e) {
+      throw new RuntimeException(e);
+    }
+
     return headerElements;
   }
 

src/main/resources/io/jenkins/plugins/thememanager/ThemeManagerPageDecorator/header.jelly

@@ -1,6 +1,6 @@
 <?jelly escape-by-default='false'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler">
   <script id="theme-manager-theme" type="application/json">{ "id": "${it.themeKey}" }</script>
-  <st:adjunct includes="io.jenkins.plugins.thememanager.header.main" />
   ${it.getHeaderHtml()}
+  <st:adjunct includes="io.jenkins.plugins.thememanager.header.main" />
 </j:jelly>

src/main/resources/io/jenkins/plugins/thememanager/header/main.js

@@ -3,4 +3,13 @@ const theme = JSON.parse(themeJson);
 
 if (theme.id && theme.id !== '') {
     document.documentElement.dataset.theme = theme.id
-}
+}
+
+
+const propertiesJson = document.getElementById('theme-manager-properties').text
+const parsedProperties = JSON.parse(propertiesJson);
+
+Object.entries(parsedProperties)
+    .forEach((obj) => document.documentElement.dataset[obj[0]
+        .replace(/[-:]/g, '_')
+    ] = obj[1]);