为什么 angular-cli 创建 component/shared/index.ts? [英] Why does angular-cli create component/shared/index.ts?

问题描述

如果我运行这个:

ng g component components/blogs

我明白了

app
+--components
| +--blogs
| |  +--shared
| |  |  +--index.ts              // what's this for?
| |  +--blogs.component.css
| |  +--blogs.component.html
| |  +--blogs.component.ts
| |  +--blogs.component.spec.ts  // unit tests!
| |  +--index.ts

其余的我都明白，但是 /blogs/shared/index.ts 有什么用?如果该组件文件夹仅用于组件，为什么组件具有共享文件夹?

I understand the rest, but what is the /blogs/shared/index.ts for? Why does a component have a shared folder if that component folder is just for the component?

推荐答案

共享目录中的 index.ts 文件的想法被称为桶.

The idea of the index.ts file in the shared dir is something called a barrel.

它的目标是巩固进口.它将导出 shared 中包含的项目以使 blogs.component.ts 中的导入更干净...

The goal of the barrel it to consolidate imports. It will export the items contained within shared to make the imports in blogs.component.ts cleaner...

app/components/blogs/shared/blogs.service.ts

export class BlogsService { ... }

app/components/blogs/shared/blog.model.ts

export class Blog { ... }

app/components/blogs/shared/index.ts

export * from './blogs.service';
export * from './blog.model';

app/components/blogs/blogs.component.ts

// without barrel
import { BlogsSerivce } from './shared/blogs.service';
import { Blog } from './shared/blog.model';

// with barrel
import { BlogService, Blog } from './shared';

如果您可以想象，随着您添加更多组件/服务/指令/模型，这会变得更加整合.

And if you can imagine this becomes much more consolidated as you add more components/services/directives/models.

参考您可以在官方风格指南(感谢 Günter Zöchbauer)

REFERENCE You can read about barrels in the official style guide (Thanks to Günter Zöchbauer)

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