feat: mermaid theme auto switch

assets/js/load-mermaid.js

@@ -0,0 +1,69 @@
+
+/*!
+  * Simple-Jekyll-Search
+  * Copyright 2015-2020, Christian Fei
+  * Licensed under the MIT License.
+  */
+
+(function(window){
+    'use strict'
+    
+      const elementCode = '.mermaid'
+      const loadMermaid = function(theme) {
+        window.mermaid.initialize({theme})
+        window.mermaid.init({theme}, document.querySelectorAll(elementCode))
+      }
+      const saveOriginalData = function(){
+        return new Promise((resolve, reject) => {
+          try {
+            var els = document.querySelectorAll(elementCode),
+                count = els.length;
+            els.forEach(element => {
+              element.setAttribute('data-original-code', element.innerHTML)
+              count--
+              if(count == 0){
+                resolve()
+              }
+            });
+          } catch (error) {
+           reject(error) 
+          }
+        })
+      }
+      const resetProcessed = function(){
+        return new Promise((resolve, reject) => {
+          try {
+            var els = document.querySelectorAll(elementCode),
+                count = els.length;
+            els.forEach(element => {
+              if(element.getAttribute('data-original-code') != null){
+                element.removeAttribute('data-processed')
+                element.innerHTML = element.getAttribute('data-original-code')
+              }
+              count--
+              if(count == 0){
+                resolve()
+              }
+            });
+          } catch (error) {
+           reject(error) 
+          }
+        })
+      } 
+    
+      const init = ()=>{
+        saveOriginalData()
+        .catch( console.error )
+        document.body.addEventListener('dark-theme-set', ()=>{
+          resetProcessed()
+          .then(loadMermaid('dark'))
+          .catch(console.error)
+        })
+        document.body.addEventListener('light-theme-set', ()=>{
+          resetProcessed()
+          .then(loadMermaid('default'))
+          .catch(console.error)
+        })
+      }
+      window.initMermaid = init
+    })(window);