posthtml-css-inline
v0.2.1
Published
Inline CSS from HTML `<style>` tags into `style` attributes.
Downloads
6
Maintainers
Readme
This is a work in progress, it's not ready for production yet.
TODO:
- [x] Support
<link rel="stylesheet">
tags - [x] Remove inlined selectors from HTML elements
- [x] Support PostCSS plugins
- [ ] Support complex selectors *
- [x] Safelist (selectors that should not be inlined)
- [x] Skip inlining on marked tags
- [ ] Juice-compatible options
- [x]
excludedProperties
- [ ]
resolveCSSVariables
- [ ]
applyHeightAttributes
- [ ]
applyWidthAttributes
- [ ]
applyAttributesTableElements
- [x]
* This needs to be implemented in PostHTML or posthtml-match-helper first.
About
This plugin will inline CSS from <style>
and <link rel="stylesheet">
tags into HTML style
attributes.
The CSS will be parsed with PostCSS, so you can use PostCSS plugins to transform the CSS before it's inlined.
Use cases:
- HTML emails
- Embedding HTML in 3rd party websites
Given something like this:
<style>
div {
color: red;
}
@media (max-width: 600px) {
.text-sm {
font-size: 16px;
}
}
</style>
<div class="text-sm">Test</div>
... it will output:
<style>
div {
color: red;
}
@media (max-width: 600px) {
.text-sm {
font-size: 16px;
}
}
</style>
<div class="text-sm" style="color: red;">Test</div>
Install
$ npm i posthtml posthtml-css-inline
Usage
To use the plugin, simply pass it to PostHTML:
import posthtml from'posthtml'
import inlineCss from'posthtml-css-inline'
posthtml([
inlineCss(options)
])
.process('your HTML')
.then(result => console.log(result.html))
Options
You may configure how inlining works by passing an options object to the plugin.
| Option | Type | Default | Description |
| --- | --- | --- | --- |
| processLinkTags
| boolean
| false
| Process <link rel="stylesheet">
tags. |
| preserveImportant
| boolean
| false
| Preserve !important
in the inlined CSS value. |
| removeInlinedSelectors
| boolean
| false
| Remove selectors that were successfully inlined from both the <style>
tag and from the HTML body. |
| postcss
| object
| {}
| Object to configure PostCSS. |
| safelist
| array
| []
| Array of selectors that should not be inlined. |
| excludedProperties
| array
| []
| Array of CSS properties that should not be inlined. |
Attributes
You may configure how inlining works on a per-element basis.
| Attribute | Description |
| --- | --- |
| no-inline
| Skip inlining on this element. |
processLinkTags
Type: boolean
Default: false
Whether to process <link rel="stylesheet">
tags.
The plugin will fetch the CSS from the URL in the href
attribute, and replace the <link>
tag with a <style>
tag containing the CSS. This <style>
tag will then be inlined into the HTML.
import posthtml from'posthtml'
import inlineCss from'posthtml-css-inline'
posthtml([
inlineCss({
processLinkTags: true
})
])
.process(`
<link rel="stylesheet" href="public/styles.css">
<p class="text-sm">small text</p>
`)
.then(result => result.html)
/* public/styles.css */
.text-sm {
font-size: 12px;
}
Result:
<p class="text-sm" style="font-size: 12px">small text</p>
preserveImportant
Type: boolean
Default: false
Whether to preserve !important
in the inlined CSS value.
For example this:
import posthtml from'posthtml'
import inlineCss from'posthtml-css-inline'
posthtml([
inlineCss({
preserveImportant: true
})
])
.process(`
<style>
.text-sm {
font-size: 12px;
}
div {
font-size: 14px !important;
}
</style>
<p class="text-sm">small text</p>
`)
.then(result => result.html)
... will output this:
<p class="text-sm" style="font-size: 14px !important">small text</p>
removeInlinedSelectors
Type: boolean
Default: false
Whether to remove selectors that were successfully inlined from both the <style>
tag and from the HTML body.
If a selector that has been inlined is also present inside an at-rule such as @media
, it will not be removed from the HTML body.
import posthtml from'posthtml'
import inlineCss from'posthtml-css-inline'
posthtml([
inlineCss({
removeInlinedSelectors: true
})
])
.process(`
<style>
.text-sm {
font-size: 12px;
}
@media (min-width: 640px) {
.text-sm {
font-size: 16px !important;
}
}
</style>
<p class="text-sm">small text</p>
`)
.then(result => result.html)
Result:
<style>
@media (min-width: 640px) {
.text-sm {
font-size: 16px !important;
}
}
</style>
<p class="text-sm" style="font-size: 12px">small text</p>
postcss
Type: object
Default: {}
You may configure PostCSS and use PostCSS plugins to transform the CSS before it's inlined.
import posthtml from'posthtml'
import inlineCss from'posthtml-css-inline'
// Imaginary PostCSS plugin that removes !important
import removeImportant from'remove-important-plugin'
posthtml([
inlineCss({
postcss: {
plugins: [
removeImportant
]
}
})
])
.process(`
<style>
.text-sm {
font-size: 12px !important;
}
@media (min-width: 640px) {
.text-sm {
font-size: 16px !important;
}
}
</style>
<p class="text-sm">small text</p>
`)
.then(result => result.html)
Result:
<style>
.text-sm {
font-size: 12px;
}
@media (min-width: 640px) {
.text-sm {
font-size: 16px;
}
}
</style>
<p class="text-sm" style="font-size: 12px">small text</p>
safelist
Type: array
Default: []
Array of selectors that should not be inlined.
[!NOTE]
The CSS*
selector is not supported when inlining, you don't need to worry about safelisting it.
import posthtml from'posthtml'
import inlineCss from'posthtml-css-inline'
posthtml([
inlineCss({
safelist: ['body', '.flex']
})
])
.process(`
<style>
.flex {
display: flex;
}
body {
color: blue;
}
p {
color: red;
}
</style>
<body>
<p class="flex">small text</p>
</body>
`)
.then(result => result.html)
Result:
<body>
<p class="flex" style="color: red">small text</p>
</body>
excludedProperties
Type: array
Default: []
Array of CSS properties that should not be inlined.
import posthtml from'posthtml'
import inlineCss from'posthtml-css-inline'
posthtml([
inlineCss({
excludedProperties: ['color', 'display']
})
])
.process(`
<style>
p {
color: red;
display: flex;
font-size: 12px;
}
</style>
<p>text</p>
`)
.then(result => result.html)
Result:
<style>
p {
color: red;
display: flex;
font-size: 12px;
}
</style>
<p style="font-size: 12px">text</p>
no-inline
You may use the no-inline
attribute on an element to prevent CSS inlining.
- when used on a
<style>
or<link>
tag, the CSS inside the tag will not be inlined - when used on any other tag, the inliner will not inline CSS on that tag
You may use any of the following attributes to achieve this on a <style>
or <link>
tag:
no-inline
data-embed
embed
prevent-inline
skip-inline
Likewise, you may use any of the following attributes to achieve this on any other tag:
no-inline
prevent-inline
skip-inline
The attribute will be removed from the tag in the resulting HTML.
import posthtml from'posthtml'
import inlineCss from'posthtml-css-inline'
posthtml([
inlineCss()
])
.process(`
<style no-inline>
p {
font-size: 12px;
}
</style>
<style>
div {
color: blue;
}
</style>
<p>small text</p>
<div no-inline>b</div>
`)
.then(result => result.html)
Result:
<style>
p {
font-size: 12px;
}
</style>
<style>
div {
color: blue;
}
</style>
<p>small text</p>
<div>b</div>