sass-style-template

Simple SCSS watcher with autoprefixer.

Why?

• I want to use SASS and LitElement for creating Web Components.
• I want to use ES Modules for CSS (CSS Modules) helping me through ES6 modules.
• I want to make it simple and decoupled from any bundle generator (snowpack, parcel, rollup, webpack)

// I don't want to use SASS directly in my code
import styles from './my-component-style.scss' 😟

Lit Element makes it easy to "shimming" CSS Modules and "using" CSS-in-JS in a simple and lightweight way

:host {
  display: block;
  color: #{'${unsafeCSS(tokens.colors.primary)}'};

  @at-root #{&}([variant=large]) {
    letter-spacing: 3px;
  }
}

p {
  background-color: #{'${unsafeCSS(tokens.colors.secondary)}'};
  :host([variant='large']) & {
    padding: calc(#{'${unsafeCSS(tokens.spaces.xlarge)}'} + 16px);
  }
}

import { css, unsafeCSS } from 'lit';
import * as tokens from 'my-design-system-tokens';

export const styles = css`
  :host {
    display: block;
    color: ${unsafeCSS(tokens.colors.primary)};
  }
  :host([variant='large']) {
    letter-spacing: 3px;
  }

  p {
    background-color: ${unsafeCSS(tokens.colors.secondary)};
  }
  :host([variant='large']) p {
    padding: calc(${unsafeCSS(tokens.spaces.xlarge)} + 16px);
  }
`;

// LitElement
import { styles } from './my-component-styles.css.js';

static get styles() {
  return [styles]
}

Or just, compile .scss files to .css file and then use ES Module Shims

CSS Modules - chromestatus

// LitElement
import styles from './style.css';
...
static get styles() {
  return [styles]
}

How it works

The first time a default template will be used to create a style file

// sass-template.tmpl
import { css } from 'lit';

export const styles = css`<% content %>`;

// my-component.scss
:host {
  display: block;
  color: desaturate(#ad141e, 20%);
}

my-component.scss --> my-component-styles.css.js

or without suffix

my-component.scss --> my-component.css.js

Following changes in the scss file (my-component.scss) will update only the content between the css`` template literal in .css.js file

// from original template
import { css } from 'lit';

// new content added later, it will not be deleted when updating scss file
import * as tokens from 'my-design-system-tokens';

export const styles = css`
  // only this part will be modified
  // new css from scss file
`;

Usage

npm i -D sass-style-template

Options

sass-style-template

// template default

const customTemplate = path.resolve('sass-template.tmpl');

// commander options
version(pkg.version, '-v, --version', 'show version number')
  .option('-s, --marker-start <string>', 'start replace position')
  .option('-e, --marker-end <string>', 'end replace position')
  .option('-g, --custom-glob <string>', 'string pattern to be matched')
  .option('-f, --css-file', 'generate css file instead of using template')
  .option('-wo, --wo-suffix', 'without suffix string `-styles`')
  .option('-j, --js-file <string>', 'file extension')
  .option('-d, --destination <string>', 'location of the output file');

Typescript (--js-file option)

// package.json
// my-component.scss --> my-component-styles.css.ts
"scripts": {
  "start": "concurrently -k -r \"npm:sass:watch\" \"npm:vite\"",
  "sass:watch": "sass-style-template -j ts"
}

Default option value

sass-template.tmpl

import { css } from 'lit';

export const styles = css`<% content %>`;

Creating a custom template file in root directory, using this name sass-template.tmpl

// https://github.com/material-components/material-web/blob/master/css-to-ts.js

import { css } from 'lit';

export const styles = css`<% content %>`;

--marker-start (-s)

start replace position : const styles = css`

--marker-end (-e)

end replace position : `; export { styles as default };

--custom-glob (g)

pattern to be matched : ./*.scss, ./src/**/*.scss

--css-file (-f)

generate css file instead of using template : undefined

--wo-suffix (-wo)

without suffix string -styles : undefined

--js-file (-j)

file extension : js

--destination (-d)

location of the output file : undefined

Example:

open-wc-vitejs-sass

Free Software.