Hello dear all steemians,
Today, I am going to share with you, that how Angular 4 Architecture works. Let's have a look to this image.
Here you can see multiple files in app folder like:

1. app.component.css

app.component.css will contain all the classes and id's of CSS file. this is actually a css file, where all the classes are defined.

2. app.component.html

app.component.html is actually an HTML file where all the tags are defined.

3. app.component.spec.ts

are automatically generated files which contain unit tests for source component.

4. app.component.ts

app.component.ts is the controller of Angular 4

5. app.module.ts

app.module.ts is a mechanism, which group components, directive, pipes, and serives that are related to each other, in such a way that combined with another module to create a web application.

For more watch this video: How Angular 4 Worked

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