# Material Web Components

> :warning: These components are a work in progress. They are pre-release and should be considered experimental, as they may undergo major changes before release. We are experimenting with alternate architectures and approaches with the goal of allowing us to bring the most correct and optimal implementation of Material components to the widest possible audiences. Visible progress may be slow, as this research is across teams and repositories so is not consistently reflected in commits to this codebase. :warning:

Material Web Components helps developers execute [Material Design](https://www.material.io) using [web components](https://developer.mozilla.org/en-US/docs/Web/Web_Components).

Built on top of the [Material Components Web](https://github.com/material-components/material-components-web) project and [LitElement](https://github.com/polymerlabs/lit-element), the Material Web Components enable a reliable development workflow to build beautiful and functional web projects.

Web Components can be seamlessly incorporated into a wide range of usage contexts. Whether you're already heavily invested in another framework or not, it's easy to incorporate Material Web Components into your site in a lightweight, idiomatic fashion.

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**[Demos](https://material-components.github.io/material-components-web-components/demos/index.html)**

## Quick start

> Note: This guide assumes you have npm installed locally.

The easiest way to try out the Material Web Components is to use one of these online tools:

  * Runs in all [supported browsers](#browser-support): [Glitch](https://glitch.com/edit/#!/material-web-components)

  * Runs in browsers with [JavaScript Modules](https://caniuse.com/#search=modules): [JSBin](http://jsbin.com/gitufet/edit?html,output), [CodePen](https://codepen.io/sorvell/pen/MGrZqp?editors=1000).

Or you can also copy [this HTML file](https://gist.githubusercontent.com/sorvell/2ec11ccde449815bc97edc1026be27a9/raw/8bab65dd5d15f657ae69493851690c5564367d13/index.html) into a local file and run it in any browser that supports JavaScript Modules.

When you're ready to use the Material Web Components in your web application:

1. Ensure the webcomponents polyfills are included in your HTML page

      - Install webcomponents polyfills

          ```npm i @webcomponents/webcomponentsjs```

      - Add webcomponents polyfills to your HTML page

          ```<script src="@webcomponents/webcomponentsjs/webcomponents-loader.js"></script>```

  1. Add one of the MWC elements to your project, for example for icon:

      ```npm i @material/mwc-icon```

  1. Import the element definition into your HTML page:

      ```<script type="module" src="@material/mwc-icon/mwc-icon.js"></script>```

      Or into your module script:

      ```import {Icon} from "@material/mwc-icon"```

  1. Create an instance of element in your HTML page, or via any framework that [supports rendering Custom Elements](https://custom-elements-everywhere.com/):

      ```<mwc-icon>sentiment_very_satisfied</mwc-icon>```

  1. Install the Polymer CLI:

      ```npm i -g polymer-cli```

  1. Run the development server and open a browser pointing to its URL:

      ```polymer serve```

  > The Material Web Components are published on [npm](https://www.npmjs.com) using JavaScript Modules.
  This means it can take advantage of the standard native JavaScript module loader available in all current major browsers.
  >
  > However, since the Material Web Components use npm convention to reference dependencies by name, a light transform to rewrite specifiers to URLs is required to get it to run in the browser. The polymer-cli's development server `polymer serve` automatically handles this transform.

  Tools like [WebPack](https://webpack.js.org/) and [Rollup](https://rollupjs.org/) can also be used to serve and/or bundle.

## Contributing guide
Below are instructions for setting up project development.

1. Clone this repo with `git clone`.
1. Install dependencies by running `npm install`
1. Build the project with `npm run build`
1. Run a development server with `npm run dev`
    - View the demos by accessing `<dev server url>`/demos/index.html
    - This will also build the project.
1. Run tests with `npm run build:tests && npm run test`
1. Run benchmarks with `npm run build:tests && npm run test:bench`

*Note:* You can debug specific tests by running `npm run test:debug -- --packages mwc-button,mwc-fab`
or you may use wildcards such as `npm run test:debug -- --packages mwc-icon-button*`
Additionally, you can run specific browsers with the `--browsers` flag. e.g.
`npm run test:debug -- --browsers Firefox` or `npm run test -- --browsers ChromeHeadless`.

### Developing Components

Components are written in [Typescript](https://typescriptlang.org), and compiled to [Javascript Modules](https://hacks.mozilla.org/2018/03/es-modules-a-cartoon-deep-dive/).

The output Javascript Modules can be used in every modern browser directly, and are supported a wide variety of popular bundler and build tools.

The components render output structure, handle styling, and manage data flow with `lit-html` while integrating with Material Design's common logic library for each component.

### Styling Components

Components define their styling using [SASS](http://sass-lang.com/).

The SASS output is built into a javascript module which exports the component's styling as a [lit-html](https://github.com/Polymer/lit-html) template.

Component styling is compiled with both `npm run build` and `npm run watch`.

To compile the component SASS manually, use `npm run build-styling`

## Useful Links

- [All Components](packages/)
- [Demos](https://material-components.github.io/material-components-web-components/demos/index.html)
- [Contributing](CONTRIBUTING.md)
- [Material.io](https://www.material.io) (external site)
- [Material Design Guidelines](https://material.io/guidelines) (external site)

## Browser Support

We officially support the last two versions of every major browser. Specifically, we test on the following browsers:

- Chrome
- Safari
- Firefox
- IE 11/Edge
- Opera
- Mobile Safari
- Chrome on Android