有一个问题，我不知道为什么
在注释下面的代码行时，不会显示问题。
platformBrowserDynamic（）。bootstrapModule（AppModule）.catch（err =＆gt; console.log（err））;
core.es5.js:1020 ERROR TypeError: Cannot read property 'map' of null
at splitDepsDsl (core.es5.js:8712)
at _def (core.es5.js:10695)
at directiveDef (core.es5.js:10652)
at View_AppComponent_Host_0 (AppComponent_Host.html:1)
at proxyClass (compiler.es5.js:14963)
at resolveDefinition (core.es5.js:8756)
at ComponentFactory_.ac_app../node_modules/@angular/core/@angular/core.es5.js.ComponentFactory_.create (core.es5.js:9859)
at ComponentFactoryBoundToModule.ac_app../node_modules/@angular/core/@angular/core.es5.js.ComponentFactoryBoundToModule.create (core.es5.js:3333)
at ApplicationRef_.ac_app../node_modules/@angular/core/@angular/core.es5.js.ApplicationRef_.bootstrap (core.es5.js:4768)
at core.es5.js:4546