Node.js regex: Find all CSS properties in a stylesheet not in the comments

Question

I am trying to use regex to query all of the attributes inside of a CSS file. My end goal is to be able to take a css file like this:

html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td,
article, aside, canvas, details, embed, 
figure, figcaption, footer, header, hgroup, 
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
}
/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure, 
footer, header, hgroup, menu, nav, section {
    display: block;
}
body {
    line-height: 1;
}
ol, ul {
    list-style: none;
}
blockquote, q {
    quotes: none;
}
blockquote:before, blockquote:after,
q:before, q:after {
    content: '';
    content: none;
}
table {
    border-collapse: collapse;
    border-spacing: 0;
}

and return a list of selectors like this:

margin, padding, border, font-size, font, vertical-align, display, list-style, quotes, content, border-collapse, border-spacing

The first step is to create a regular expression than only matches all of the attributes in the css file, and only those that are not selectors (ie. a:hover) or inside of comments.

Right now all I have is /(?:([\w\d\S\-\_]+)\:)/g, which works, but still queries selectors and text inside of comments.

"and return a list of selectors like this:" Is requirement to return properties set at css ? — guest271314
– guest271314, Commented Jan 12, 2016 at 16:14
You could first filter out the comments, and then run your regex — Adi Levin
– Adi Levin, Commented Jan 12, 2016 at 16:14
@guest271314 no I just want to return the attributes themselves. margin <- this and not this -> margin: 0; — watzon
– watzon, Commented Jan 12, 2016 at 16:17

guest271314 · Accepted Answer · 2016-01-12 23:25:19Z

2

Try using String.prototype.replace() with RegExp /\/\*.*\*\/|(-moz-|-ms-|-o-|-webkit-)+\w+(?=:)/g to match , remove comment text , vendor prefixes ; String.prototype.match() with RegExp /[a-z-]+(?=:[^before|after|hover])/ig to match characters "a" through "z" or "-" case insensitive, followed by ":" , not followed by "before" or "after"

var style = document.querySelector("style");
var props = style.textContent
            // remove comments, vendor prefixes
            .replace(/\/\*.*\*\/|(-moz-|-ms-|-o-|-webkit-)+\w+(?=:)/g,"")
            // negate `:hover`
            .match(/[a-z-]+(?=:[^before|after|hover])/ig);
console.log(props)

html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td,
article, aside, canvas, details, embed, 
figure, figcaption, footer, header, hgroup, 
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
}
/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure, 
footer, header, hgroup, menu, nav, section {
    display: block;
}
body {
    line-height: 1;
}
ol, ul {
    list-style: none;
}
blockquote, q {
    quotes: none;
}
blockquote:before, blockquote:after,
q:before, q:after {
    content: '';
    /* duplicate `content` property here */
    /* content: none; */
}
table {
    border-collapse: collapse;
    border-spacing: 0;
}

table:hover {
  color:blue;
  -moz-animation: name 1s;
}

edited Jan 12, 2016 at 23:25

answered Jan 12, 2016 at 16:21

guest271314

1

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3 Comments

watzon Over a year ago

This is good, but I actually need it to do a couple more things. As it is right now this code will still match on :hover and other selectors as well as some special selectors like [href^='https']. Here is a full example of the stylesheet I'm matching on regexr.com/3cih2. I'd also like to have it not match browser-prefix attributes like -moz-*

watzon Over a year ago

Maybe I was wrong on that one. I know there was one selector that was returning a false positive, but I can't remember where

guest271314 Over a year ago

@mascaliente "I know there was one selector that was returning a false positive, but I can't remember where" ? Same link regexr.com/3cih2 ? Tried js at updated post ?

Josh Crozier · Accepted Answer · 2016-01-12 17:03:50Z

2

You may not need regular expressions for this.

You can access the stylesheet with JavaScript, then iterate over the stylesheet's cssRules object and split each declaration at ; then split each property/value pair at the : character.

It's worth pointing out that this method will expand the shorthand properties since the cssText property consists of the computed properties/values.

function getPropertiesFromStylesheet(stylsheetIndex) {
  var stylesheet = document.styleSheets[stylsheetIndex],
    rules = stylesheet.cssRules,
    properties = [];

  if (stylesheet) {
    Object.keys(rules).forEach(function(key) {
      rules[key].style.cssText.split(';').forEach(function(declaration) {
        if (declaration) {
          properties.push(declaration.split(':')[0].trim());
        }
      });
    });
  }

  return properties;
}

document.body.textContent = getPropertiesFromStylesheet(0);

html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td,
article, aside, canvas, details, embed, 
figure, figcaption, footer, header, hgroup, 
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
}
/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure, 
footer, header, hgroup, menu, nav, section {
    display: block;
}
body {
    line-height: 1;
}
ol, ul {
    list-style: none;
}
blockquote, q {
    quotes: none;
}
blockquote:before, blockquote:after,
q:before, q:after {
    content: none;
}
table {
    border-collapse: collapse;
    border-spacing: 0;
}

answered Jan 12, 2016 at 17:03

Josh Crozier

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2 Comments

watzon Over a year ago

This is nice, but requires browser javascript. This is actually a node.js script

enhzflep Over a year ago

@mascaliente - so then edit your question to include the relevant tag and avoid wasting anyone else's time. :thumbs-down:

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