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postcss-calc
PostCSS plugin to reduce
calc()
.
This plugin reduce calc()
references whenever it's possible.
This can be particularly useful with the postcss-custom-properties plugin.
Note: When multiple units are mixed together in the same expression, the calc()
statement is left as is, to fallback to the w3c calc() feature.
Installation
$ npm install postcss-calc
Usage
// dependencies
var fs = require("fs")
var postcss = require("postcss")
var calc = require("postcss-calc")
// css to be processed
var css = fs.readFileSync("input.css", "utf8")
// process css
var output = postcss()
.use(calc())
.process(css)
.css
Example (with postcss-custom-properties enabled as well):
// dependencies
var fs = require("fs")
var postcss = require("postcss")
var customProperties = require("postcss-custom-properties")
var calc = require("postcss-calc")
// css to be processed
var css = fs.readFileSync("input.css", "utf8")
// process css
var output = postcss()
.use(customProperties())
.use(calc())
.process(css)
.css
Using this input.css
:
:root {
--main-font-size: 16px;
}
body {
font-size: var(--main-font-size);
}
h1 {
font-size: calc(var(--main-font-size) * 2);
height: calc(100px - 2em);
margin-bottom: calc(
var(--main-font-size)
* 1.5
)
}
you will get:
body {
font-size: 16px
}
h1 {
font-size: 32px;
height: calc(100px - 2em);
margin-bottom: 24px
}
Checkout tests for more examples.
Options
precision
(default: 5
)
Allow you to definine the precision for decimal numbers.
var out = postcss()
.use(calc({precision: 10}))
.process(css)
.css
preserve
(default: false
)
Allow you to preserve calc() usage in output so browsers will handle decimal precision themselves.
var out = postcss()
.use(calc({preserve: true}))
.process(css)
.css
warnWhenCannotResolve
(default: false
)
Adds warnings when calc() are not reduced to a single value.
var out = postcss()
.use(calc({warnWhenCannotResolve: true}))
.process(css)
.css
mediaQueries
(default: false
)
Allows calc() usage as part of media query declarations.
var out = postcss()
.use(calc({mediaQueries: true}))
.process(css)
.css
selectors
(default: false
)
Allows calc() usage as part of selectors.
var out = postcss()
.use(calc({selectors: true}))
.process(css)
.css
Example:
div[data-size="calc(3*3)"] {
width: 100px;
}
Contributing
Work on a branch, install dev-dependencies, respect coding style & run tests before submitting a bug fix or a feature.
$ git clone https://github.com/postcss/postcss-calc.git
$ git checkout -b patch-1
$ npm install
$ npm test