Loading multiple stylesheet for a component in Angular2

Question

I am building an angular2 application. I am facing multiple problems when i try to load multiple stylesheet for the same component. Here is a the code of what i am doing:

import { Component } from '@angular/core';

@Component({
selector: 'my-tag',
templateUrl: 'my-tag.component.html',
styleUrls: [
    './style1.css',
    './style2.css'
    ]
})
export class MyTagComponent{}

Now here are my problems:

When i try to include the the css file from other directory like this:

styleUrls: [
    './style1.css',
    '../public/style2.css'
]

I get the error

Uncaught Error: Expected 'styles' to be an array of strings.

in browser console.

I then included the second stylesheet style2.css in the directory of the component and wrote the first snippet. Now the style is being loaded but it is being loaded globally. The second stylesheet has class names that clash with the bootstrap and instead of bootstrap's style the second stylesheet's style is being applied globally, i.e. other components' templates are being styled from second stylesheet.

Shouldn't the urls listed in styleUrls be applied only on the component and not do harm to other components?

Can anyone tell me how to load multiple css files for the a specific component without being applied globally.

I have also tried the following workarounds but the style is being applied on all the components that i made.

styles: [
      require('./style1.css').toString(),
      require('../public/style2.css').toString()
 ]

P.S. I am using webpack as the module bundler for my project.

webpack.config(excerpt)

 {
    test: /\.css$/,
    exclude: helpers.root('src', 'app'),
    loader: ExtractTextPlugin.extract('style', 'css?sourceMap')
  },
  {
    test: /\.css$/,
    include: helpers.root('src', 'app'),
    loader: 'raw'
  }

Solution 1

I have seen this approach used:

@Component({
    selector: 'app',
    templateUrl: './app.component.html',
    styleUrls: ['./app.component.css']
})
export class AppComponent {
}

Where app.component.css has multiple imports in it, thus:

@import url('/assets/plugins/bootstrap-datepicker/css/bootstrap-datepicker.css');
@import url('/assets/plugins/bootstrap-datepicker/css/bootstrap-datepicker3.css');
@import url('/assets/plugins/ionRangeSlider/css/ion.rangeSlider.css');
@import url('/assets/plugins/ionRangeSlider/css/ion.rangeSlider.skinNice.css');

I hope this helps.

Solution 2

We include the template and CSS files by setting the templateUrl and styleUrls metadata properties respectively. Because these files are co-located with the component, it would be nice to refer to them by name without also having to specify a path back to the root of the application.

We can change the way Angular calculates the full URL be setting the component metadata's moduleId property to module.id.

@Component({
  selector: 'my-tag',
  moduleId: module.id,
  templateUrl: 'my-tag.component.html',
  styleUrls:  ['style1.css', 'style2.css']
})
export class MyTagComponent { }

Update#1

for webpack:

Try to use the 'to-string-loader' for css in webpack config.

{ test: /\.css$/, loaders: ['to-string-loader', 'css-loader'] }

Hope will work for you.

Comments

[kanra-san]

I am using webpack as module bundler. Your solution works when we have systemjs as module bundler.

[Avnesh Shakya]

I added updated for webpack, check out Update#1 above. Thanks

[kanra-san]

I tried with your configuration but no luck. I have posted my webpack.config above. Correct me if im wrong but theto-string-loader does the same work as toString() doesn't it? As i have mentioned above, when i add toString() the style sheet is loaded but it is being loaded globally and every other component is affected by it.

[Avnesh Shakya]

Try to add encapsulation: ViewEncapsulation.None in your component meta tag for that you have to import it => import {ViewEncapsulation} from '@angular/core'; Checkout this.

[kanra-san]

actually i have already tried that too but it was also of no use.

[rosstripi]

In the current version of Angular 4, couldn't you just do those import statements in the global styles.css file?

[kanra-san]

@davaus Doesn't that kinda defeat the purpose of passing values as an array in styleUrls. The meta's name it self suggest multiple style-sheets.

[davaus]

Hi Kanra-san. I agree; but the array didn't work (I tried it) and this method did.....