problems:

• 1. 组件实现单例: esm, context
• 2. 题：解析tpl

                  
      const parseHTML = (tpl) => {
          let parsedList = []; // {tagName: '', type: 'start' | 'end'}[]
          while (tpl.trim()) {
              const tagName = tpl.match(/<\/?(\w+)+?/)?.[1];
              
              if (!tagName) {
                  return parsedList;
              }
  
              const oneTag = tpl.match(new RegExp(`(<\/?${tagName}[^>]*)+?`))[0];
              
              const item = {
                  tagName,
                  type: 'start'
              };
  
              if (oneTag.includes('/')) {
                  item.type = 'end';
              }
  
              parsedList.push(item);
  
              tpl = tpl.replace(oneTag, '');
          }
  
          return parsedList;
      };
  
  
      const createAst = list => {
  
          if (!list.length) {
              return list;
          }
  
          let root = {...list.shift()};
  
          const stack = [root];
  
          for (const {type, tagName} of list) {
              const head = stack[stack.length - 1];
  
              if (type === 'start') {
                  head.children = head.children || [];
                  const item = {tagName};
                  head.children.push(item);
                  stack.push(item);
              } else {
                  stack.pop();
              }
              
          }
  
          return root;
      };
  
      createAst(parseHTML());
                  
              

• 很好的资料: https://zhuanlan.zhihu.com/p/274272630

• infer关键字：
      1. 2.8新增的
      2. 可以解包：比如解Map 
          type GetMapKV<T> = T extends Map<infer K, infer V> ? [K, V] : T; 
          type KV = GetMapKV<MyMap>; // [string, number[]]
      3. ？待继续
              

• useMemo 用 await 会block吗？ 不会，因为外面没有await
• 书：https://github.com/imarvinle/free-programming-books-zh_CN
• 书：https://www.zhihu.com/question/40328549/answer/1584954363
• cep: https://kuaizi-co.github.io/blog/post/adobe-cep-get-started.html#%E5%9F%BA%E4%BA%8E-vue-%E5%BC%80%E5%8F%91%E6%89%A9%E5%B1%95%E6%8F%92%E4%BB%B6
• 图解react: http://www.7km.top/ / https://github.com/7kms/react-illustration-series
• 协议必看：https://upload-images.jianshu.io/upload_images/6688932-86aae0494e079c2a.png
• 电子书： https://github.com/xmgi/it-ebooks-cn
• 改字符集： ALTER TABLE User CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
• Captuocr
• https://potoyang.gitbook.io/spring-in-action-v4/