我创建了一个简单的 Angular 9 项目，其中只有几个简单的组件。我使用以下方法添加了角材料：
ng add @angular/material
完成后，我运行npm start并注意到它开始使用一堆我不在我的应用程序中使用的@angular/material/* 组件编译整个@angular：
Compiling @angular/cdk/keycodes : es2015 as esm2015
Compiling @angular/animations : es2015 as esm2015
Compiling @angular/compiler/testing : es2015 as esm2015
Compiling @angular/core : es2015 as esm2015
Compiling @angular/cdk/collections : es2015 as esm2015
Compiling @angular/common : es2015 as esm2015
Compiling @angular/animations/browser : es2015 as esm2015
Compiling @angular/cdk/observers : es2015 as esm2015
Compiling @angular/core/testing : es2015 as esm2015
Compiling @angular/cdk/platform : es2015 as esm2015
Compiling @angular/cdk/accordion : es2015 as esm2015
Compiling @angular/cdk/portal …