CSS Modules: Values

Pass arbitrary values between your module files

## Usage

/* colors.css */
@value primary: #BF4040;
@value secondary: #1F4F7F;
.text-primary {
color: primary;
}
.text-secondary {
color: secondary;
}
/* breakpoints.css */
@value small: (max-width: 599px);
@value medium: (min-width: 600px) and (max-width: 959px);
@value large: (min-width: 960px);
/* my-component.css */
/* alias paths for other values or composition */
@value colors: "./colors.css";
/* import multiple from a single file */
@value primary, secondary from colors;
/* make local aliases to imported values */
@value small as bp-small, large as bp-large from "./breakpoints.css";
/* value as selector name */
@value selectorValue: secondary-color;
.selectorValue {
color: secondary;
}
.header {
composes: text-primary from colors;
box-shadow: 0 0 10px secondary;
}
@media bp-small {
.header {
box-shadow: 0 0 4px secondary;
}
}
@media bp-large {
.header {
box-shadow: 0 0 20px secondary;
}
}

If you are using Sass along with this PostCSS plugin, do not use the colon `:` in your `@value` definitions. It will cause Sass to crash.

Note also you can import multiple values at once but can only define one value per line.

@value a: b, c: d; /* defines a as "b, c: d" */

## Justification

See this PR for more background

# License

ISC

# With thanks

- Mark Dalgleish
- Tobias Koppers
- Josh Johnston

Glen Maddern, 2015.