update-9.1
Forms
If you use ngForm element selector to create Angular Forms, you should instead use ng-form.
AppModule 抽屉
不再需要 entryComponents 和 ANALYZE_FOR_ENTRY_COMPONENTS
If you have specified any entryComponents in your NgModules or had any uses of ANALYZE_FOR_ENTRY_COMPONENTS, you can remove them. They are no longer required with the Ivy compiler and runtime.
以前，NgModule 定义中的 entryComponents 数组用于告诉编译器将动态创建和插入哪些组件。改用 Ivy 后，将不再需要它们，并且可以从现有模块声明中删除 entryComponents 数组。ANALYZE_FOR_ENTRY_COMPONENTS 注入令牌也是如此。