Fix：优化公式插件，适配创建多个实例的情况

simple-mind-map/index.js

@@ -35,6 +35,7 @@ class MindMap {
    * @param {defaultOpt} opt
    */
   constructor(opt = {}) {
+    MindMap.instanceCount++
     // 合并选项
     this.opt = this.handleOpt(merge(defaultOpt, opt))
     // 预处理节点数据
@@ -618,6 +619,7 @@ class MindMap {
     this.el.innerHTML = ''
     this.el = null
     this.removeCss()
+    MindMap.instanceCount--
   }
 }
 
@@ -634,6 +636,7 @@ MindMap.hasPlugin = plugin => {
     return item === plugin
   })
 }
+MindMap.instanceCount = 0
 
 // 定义新主题
 MindMap.defineTheme = (name, config = {}) => {

simple-mind-map/src/plugins/Formula.js

@@ -4,6 +4,7 @@ import { getChromeVersion, htmlEscape } from '../utils/index'
 import { getBaseStyleText, getFontStyleText } from './FormulaStyle'
 
 let extended = false
+const QuillFormula = Quill.import('formats/formula')
 
 // 数学公式支持插件
 // 该插件在富文本模式下可用
@@ -18,6 +19,18 @@ class Formula {
     this.cssEl = null
     this.addStyle()
     this.extendQuill()
+    this.onDestroy = this.onDestroy.bind(this)
+    this.mindMap.on('beforeDestroy', this.onDestroy)
+  }
+
+  onDestroy() {
+    const instanceCount = Object.getPrototypeOf(this.mindMap).constructor
+      .instanceCount
+    // 如果思维导图实例数量变成0了，那么就恢复成默认的
+    if (instanceCount <= 1) {
+      extended = false
+      Quill.register('formats/formula', QuillFormula, true)
+    }
   }
 
   init() {
@@ -55,7 +68,6 @@ class Formula {
     if (extended) return
     extended = true
 
-    const QuillFormula = Quill.import('formats/formula')
     const self = this
 
     class CustomFormulaBlot extends QuillFormula {
@@ -173,11 +185,13 @@ class Formula {
   // 插件被移除前做的事情
   beforePluginRemove() {
     this.removeStyle()
+    this.mindMap.off('beforeDestroy', this.onDestroy)
   }
 
   // 插件被卸载前做的事情
   beforePluginDestroy() {
     this.removeStyle()
+    this.mindMap.off('beforeDestroy', this.onDestroy)
   }
 }