lepu-test-platform-web/node_modules/postcss-import/README.md

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# postcss-import
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> [PostCSS](https://github.com/postcss/postcss) plugin to transform `@import`
rules by inlining content.
This plugin can consume local files, node modules or web_modules.
To resolve path of an `@import` rule, it can look into root directory
(by default `process.cwd()`), `web_modules`, `node_modules`
or local modules.
_When importing a module, it will look for `index.css` or file referenced in
`package.json` in the `style` or `main` fields._
You can also provide manually multiples paths where to look at.
**Notes:**
- **This plugin should probably be used as the first plugin of your list.
This way, other plugins will work on the AST as if there were only a single file
to process, and will probably work as you can expect**.
- This plugin works great with
[postcss-url](https://github.com/postcss/postcss-url) plugin,
which will allow you to adjust assets `url()` (or even inline them) after
inlining imported files.
- In order to optimize output, **this plugin will only import a file once** on
a given scope (root, media query...).
Tests are made from the path & the content of imported files (using a hash
table).
If this behavior is not what you want, look at `skipDuplicates` option
- **If you are looking for glob, or sass like imports (prefixed partials)**,
please look at
[postcss-easy-import](https://github.com/trysound/postcss-easy-import)
(which use this plugin under the hood).
- Imports which are not modified (by `options.filter` or because they are remote
imports) are moved to the top of the output.
- **This plugin attempts to follow the CSS `@import` spec**; `@import`
statements must precede all other statements (besides `@charset`).
## Installation
```console
$ npm install postcss-import
```
## Usage
Unless your stylesheet is in the same place where you run postcss
(`process.cwd()`), you will need to use `from` option to make relative imports
work.
```js
// dependencies
var fs = require("fs")
var postcss = require("postcss")
var atImport = require("postcss-import")
// css to be processed
var css = fs.readFileSync("css/input.css", "utf8")
// process css
postcss()
.use(atImport())
.process(css, {
// `from` option is needed here
from: "css/input.css"
})
.then(function (result) {
var output = result.css
console.log(output)
})
```
`css/input.css`:
```css
/* can consume `node_modules`, `web_modules` or local modules */
@import "cssrecipes-defaults"; /* == @import "../node_modules/cssrecipes-defaults/index.css"; */
@import "normalize.css"; /* == @import "../node_modules/normalize.css/normalize.css"; */
@import "foo.css"; /* relative to css/ according to `from` option above */
@import "bar.css" (min-width: 25em);
body {
background: black;
}
```
will give you:
```css
/* ... content of ../node_modules/cssrecipes-defaults/index.css */
/* ... content of ../node_modules/normalize.css/normalize.css */
/* ... content of css/foo.css */
@media (min-width: 25em) {
/* ... content of css/bar.css */
}
body {
background: black;
}
```
Checkout the [tests](test) for more examples.
### Options
### `filter`
Type: `Function`
Default: `() => true`
Only transform imports for which the test function returns `true`. Imports for
which the test function returns `false` will be left as is. The function gets
the path to import as an argument and should return a boolean.
#### `root`
Type: `String`
Default: `process.cwd()` or _dirname of
[the postcss `from`](https://github.com/postcss/postcss#node-source)_
Define the root where to resolve path (eg: place where `node_modules` are).
Should not be used that much.
_Note: nested `@import` will additionally benefit of the relative dirname of
imported files._
#### `path`
Type: `String|Array`
Default: `[]`
A string or an array of paths in where to look for files.
#### `plugins`
Type: `Array`
Default: `undefined`
An array of plugins to be applied on each imported files.
#### `resolve`
Type: `Function`
Default: `null`
You can provide a custom path resolver with this option. This function gets
`(id, basedir, importOptions)` arguments and should return a path, an array of
paths or a promise resolving to the path(s). If you do not return an absolute
path, your path will be resolved to an absolute path using the default
resolver.
You can use [resolve](https://github.com/substack/node-resolve) for this.
#### `load`
Type: `Function`
Default: null
You can overwrite the default loading way by setting this option.
This function gets `(filename, importOptions)` arguments and returns content or
promised content.
#### `skipDuplicates`
Type: `Boolean`
Default: `true`
By default, similar files (based on the same content) are being skipped.
It's to optimize output and skip similar files like `normalize.css` for example.
If this behavior is not what you want, just set this option to `false` to
disable it.
#### `addModulesDirectories`
Type: `Array`
Default: `[]`
An array of folder names to add to [Node's resolver](https://github.com/substack/node-resolve).
Values will be appended to the default resolve directories:
`["node_modules", "web_modules"]`.
This option is only for adding additional directories to default resolver. If
you provide your own resolver via the `resolve` configuration option above, then
this value will be ignored.
#### Example with some options
```js
var postcss = require("postcss")
var atImport = require("postcss-import")
postcss()
.use(atImport({
path: ["src/css"],
}))
.process(cssString)
.then(function (result) {
var css = result.css
})
```
## `dependency` Message Support
`postcss-import` adds a message to `result.messages` for each `@import`. Messages are in the following format:
```
{
type: 'dependency',
file: absoluteFilePath,
parent: fileContainingTheImport
}
```
This is mainly for use by postcss runners that implement file watching.
---
## CONTRIBUTING
* ⇄ Pull requests and ★ Stars are always welcome.
* For bugs and feature requests, please create an issue.
* Pull requests must be accompanied by passing automated tests (`$ npm test`).
## [Changelog](CHANGELOG.md)
## [License](LICENSE)