Add fallback option

README.md

@@ -12,19 +12,13 @@
 npm i highlightjs-lang.js
 ```
 
-### Bower
-
-```bash
-bower install highlightjs-lang
-```
-
 #### Getting the library from CDN
 
 ```html
-<script src="//cdn.jsdelivr.net/npm/highlightjs-lang.js@1.1.0/dist/highlightjs-lang.min.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/highlightjs-lang.js@latest/dist/highlightjs-lang.min.js"></script>
 ```
 
-highlightjs-lang.js 1.1.0 is known to work with highlight.js 11.3.1.
+highlightjs-lang.js 1.1.0 is known to work with highlight.js 11.3.1+
 
 ## Usage
 
@@ -33,6 +27,7 @@ Download plugin and include file after highlight.js:
 ```html
 <script src="path/to/highlight.min.js"></script>
 
+<!-- Load plugin: -->
 <script src="path/to/highlightjs-lang.min.js"></script>
 ```
 
@@ -57,7 +52,7 @@ Initialize plugin after highlight.js:
 ```js
 hljs.highlightAll();
 
-hljs.initLangOnLoad();
+hljs.initLangOnLoad();  //  <-- init plugin
 ```
 
 Here’s an equivalent way to calling `initLangBlock` using jQuery:
@@ -77,6 +72,7 @@ After version 1.1.0 plugin has optional parameter `options` - for custom setup:
 version | name          | type    | default value | description
 --------|---------------|---------|---------------|-----------------------
 v1.1.0  | overrideNames | object  | {}            | [Override the default language names](#overrideNames)
+v1.1.1  | fallback    | func(str): str | (lang) => lang | [Fallback to convert unknown names](#fallback)
 
 ### Examples of using
 
@@ -98,9 +94,11 @@ If you want to override the default language name, you can specify a _overridden
 
 ```js
 var myOptions = {
+    // ...
     overrideNames: {
         cs: 'C#',
-    }
+    },
+    // ...
 };
 ```
 
@@ -118,6 +116,26 @@ In both cases language name will be `C#`.
 
 > [List of default language names](https://github.com/wcoder/highlightjs-lang.js/blob/master/src/highlightjs-lang.js#L4-L10)
 
+### fallback
+
+Specifying the desired format for undeclared language names:
+
+```js
+var myOptions = {
+  // ...
+  fallback: function (lang) {
+    return '~~' + lang;
+  },
+  // ...
+};
+```
+
+Convert all undeclared language names to names with `~~` prefix:
+
+```
+xyz -> ~~xyz
+```
+
 ## Skipping some blocks
 
 (Applies to `hljs.initLangOnLoad()` initialization only.)

index.html

@@ -17,11 +17,19 @@
   <script src="dist/highlightjs-lang.min.js"></script>
   <script>
     hljs.highlightAll();
+
+    // init plugin:
     hljs.initLangOnLoad(
     {
       overrideNames: {
-        cpp: 'C++',
-      }
+        dart: 'Dart',
+      },
+      fallback: function (lang) {
+        if (lang === 'php') {
+          return '$ PHP $';
+        }
+        return lang;
+      },
     }
     );
   </script>

src/highlightjs-lang.js

@@ -56,7 +56,7 @@
     if (lang !== '') {
       var langPanel = document.createElement('div');
       langPanel.className = 'hljs-lang';
-      langPanel.textContent = convertLangName(lang, internalOptions.overrideNames);
+      langPanel.textContent = convertLangName(lang, internalOptions);
       element.parentNode.insertBefore(langPanel, element);
     }
   }
@@ -70,6 +70,7 @@
     options = options || {};
     return {
       overrideNames: getOverrideNamesOption(element, langKey, options),
+      fallback: getFallbackOption(options),
     };
   }
 
@@ -91,6 +92,16 @@
     return overrideNames;
   }
 
+  function getFallbackOption (options) {
+    return !!options.fallback
+      ? options.fallback
+      : defaultFallbackOption;
+  }
+
+  function defaultFallbackOption (langKey) {
+    return langKey;
+  }
+
   function getLangNameFromElement (element) {
     var classes = element.className.split(' ');
     var lang = getLangNameFromClasses(classes);
@@ -105,9 +116,9 @@
     return '';
   }
 
-  function convertLangName(langKey, overrideNamesMap)
+  function convertLangName(langKey, options)
   {
-    var overriddenLangName = overrideNamesMap[langKey];
+    var overriddenLangName = options.overrideNames[langKey];
     if (!!overriddenLangName) {
       return overriddenLangName;
     }
@@ -117,7 +128,7 @@
       return langName;
     }
 
-    return langKey;
+    return options.fallback(langKey);
   }
 
   /**