jhildenbiddleget-css-data
A micro-library for collecting stylesheet data from link and style nodes.
Features
- Collects CSS data from
<link>and<style>nodes - Collects static Node.textContent or live CSS Object Model (CSSOM) data
- Returns CSS data as a concatenated string and a DOM-ordered array of strings
- Allows document, iframe, and shadow DOM traversal
- Handles
@importrules - Handles absolute and relative URLs
- Inspect, modify and/or filter CSS data from each node
- Modify XHR object before each request
- UMD and ES6 modules available
- Compatible with modern and legacy browsers (IE9+)
- Lightweight (less than 1.5k min+gzip) and dependency-free
Installation
NPM:
npm install get-css-data --save// file.js
import getCssData from 'get-css-data';
getCssData({
onComplete: function(cssText, cssArray, nodeArray) {
// Do stuff...
}
});Git:
git clone https://github.com/jhildenbiddle/get-css-data.gitCDN (jsdelivr.com shown, also on unpkg.com):
<!-- ES5 (latest v2.x.x) -->
<script src="https://cdn.jsdelivr.net/npm/get-css-data@2"></script>
<script>
getCssData({
onComplete: function(cssText, cssArray, nodeArray) {
// Do stuff...
}
});
</script><!-- ES6 module (latest v2.x.x) -->
<script type="module">
import getCssData from 'https://cdn.jsdelivr.net/npm/get-css-data@2/dist/get-css-data.esm.min.js';
getCssData({
onComplete(cssText, cssArray, nodeArray) {
// Do stuff...
}
});
</script>Example
HTML:
<!-- file.html -->
<head>
<link rel="stylesheet" href="style1.css">
<style>
@import "style2.css";
p { color: blue; }
</style>
</head>CSS:
/* style1.css */
p { color: red; }/* style2.css */
p { color: green; }JavaScript (see Options for details)
getCssData({
onComplete: function(cssText, cssArray, nodeArray) {
console.log(cssText); // 1
console.log(cssArray); // 2
console.log(nodeArray); // 3
}
});
// 1 => 'p { color: red; } p { color: green; } p { color: blue; }'
// 2 => ['p { color: red; }', 'p { color: green; } p { color: blue; }']
// 3 => [<linkElement>, <styleElement>]Options
Example
// Default values shown
getCssData({
rootElement : document,
include : 'link[rel=stylesheet],style',
exclude : '',
filter : '',
skipDisabled: true,
useCSSOM : false,
onBeforeSend: function(xhr, node, url) {
// ...
},
onSuccess: function(cssText, node, url) {
// ...
},
onError: function(xhr, node, url) {
// ...
},
onComplete: function(cssText, cssArray, nodeArray) {
// ...
}
});options.rootElement
- Type:
object - Default:
document
Root element to traverse for <link> and <style> nodes.
Examples
// Document
getCssData({
rootElement: document // default
});
// Iframe (must be same domain with content loaded)
getCssData({
rootElement: (myIframe.contentDocument || myIframe.contentWindow.document)
});
// Shadow DOM
getCssData({
rootElement: myElement.shadowRoot
});options.include
- Type:
string - Default:
"link[rel=stylesheet],style"
CSS selector matching <link> and <style> nodes to collect data from. The default value includes all style and link nodes.
Example
getCssData({
// Include only <link rel="stylesheet"> nodes
// with an href that does not contains "bootstrap"
include: 'link[rel=stylesheet]:not([href*=bootstrap])',
});options.exclude
- Type:
string
CSS selector matching <link> and <style> nodes to exclude from those matched by options.include.
Example
getCssData({
// Of matched `include` nodes, exclude any node
// with an href that contains "bootstrap"
exclude: '[href*=bootstrap]',
});options.filter
- Type:
object
Regular expression used to filter node CSS data. Each block of CSS data is tested against the filter, and only matching data is processed.
Example
getCssData({
// Test each block of CSS for the existence
// of ".myclass". If found, process the CSS.
// If not, ignore the CSS.
filter: /\.myclass/,
});options.skipDisabled
- Type:
boolean - Default:
true
Determines if disabled stylesheets will be skipped while collecting CSS data.
Example
getCssData({
skipDisabled: true // default
});options.useCSSOM
- Type:
boolean - Default:
false
Determines how CSS data will be collected from <style> nodes.
When false, static CSS data is collected by reading each node's textContent value. This method is fast, but the data collected will not reflect changes made using the deleteRule() or insertRule() methods. When true, live CSS data is collected by iterating over each node's CSSRuleList and concatenating all CSSRule.cssText values into a single string. This method is slower, but the data collected accurately reflects all changes made to the stylesheet.
Keep in mind that browsers often drop unrecognized selectors, properties, and values when parsing static CSS. For example, Chrome/Safari will drop declarations with Mozilla's -moz- prefix, while Firefox will drop declarations with Chrome/Safari's -webkit prefix . This means that data collected when this options is set to true will likely vary between browsers and differ from the static CSS collected when it is set to false.
Example
getCssData({
useCSSOM: false // default
});options.onBeforeSend
- Type:
function - Arguments:
- xhr: The XHR
objectcontaining details of the request - node: The source node
objectreference - url: The source URL
string(<link>href or@importurl)
- xhr: The XHR
Callback before each XMLHttpRequest (XHR) is sent. Allows modifying the XML object by setting properties, calling methods, or adding event handlers.
Example
getCssData({
onBeforeSend: function(xhr, node, url) {
// Domain-specific XHR settings
if (/some-domain.com/.test(url)) {
xhr.withCredentials = true;
xhr.setRequestHeader("foo", "1");
xhr.setRequestHeader("bar", "2");
}
}
});options.onSuccess
- Type:
function - Arguments:
- cssText: A
stringof CSS text fromnodeandurl - node: The source node
objectreference - url: The source URL
string(<link>href,@importurl, or page url for<style>data)
- cssText: A
Callback after CSS data has been collected from each node. Allows modifying the CSS data before it is added to the final output by returning any string value or skipping the CSS data by returning false or an empty string ("").
Note that the order in which <link> and @import CSS data is "successfully" collected (thereby triggering this callback) is not guaranteed as these requests are asynchronous. To access CSS data in DOM order, use the cssArray argument passed to the options.oncomplete callback.
Example
getCssData({
onSuccess: function(cssText, node, url) {
// Replace all instances of "color: red" with "color: blue"
const newCssText = cssText.replace(/color:\s*red\s;/g, 'color: blue;');
return newCssText;
}
});options.onError
- Type:
function - Arguments:
- xhr: The XHR
objectcontaining details of the request - node: The source node
objectreference - url: The source URL
string(<link>href or@importurl)
- xhr: The XHR
Callback after <link> or @import request has failed or when
xhr.responseText appears to be HTML instead of CSS.
Example
getCssData({
onError: function(xhr, node, url) {
console.log(xhr.status); // 1
console.log(xhr.statusText); // 2
}
});
// 1 => '404'
// 2 => 'Not Found'options.onComplete
- Type:
function - Arguments:
- cssText: A
stringof concatenated CSS text from all nodes in DOM order. - cssArray: An
arrayof per-node CSS text in DOM order. The node containing each CSS text block is available at the same nodeArray index. - nodeArray: An
arrayof processed<style>and<link>nodes in DOM order. The CSS text for each node is available at the same cssArray index.
- cssText: A
Callback after CSS data has been collected from all nodes.
Example
getCssData({
onComplete: function(cssText, cssArray, nodeArray) {
// ...
}
});Contact
- Create a Github issue for bug reports, feature requests, or questions
- Follow @jhildenbiddle for announcements
- Add a ⭐️ star on GitHub or ❤️ tweet to support the project!
License
This project is licensed under the MIT License. See the LICENSE for details.
Copyright (c) John Hildenbiddle (@jhildenbiddle)